Pala¨ontol Z (2011) 85:201–229 DOI 10.1007/s12542-010-0088-3

RESEARCH PAPER

Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) from the Silurian of Gotland, Sweden

Ole A. Hoel

Received: 23 September 2010 / Accepted: 1 October 2010 / Published online: 13 November 2010 Ó The Author(s) 2010. This article is published with open access at Springerlink.com

Abstract Twelve species of Brachiopods are described short ranged and occurs in low-energy environments in the from the Silurian of Gotland, six furcitellinines and six latest Llandovery. The species belonging to the Stroph- ‘‘strophodontids.’’ One is new—Strophodonta hoburgensis odontidae (Strophodonta hoburgensis n. sp.) and Shalerii- n. sp. The furcitellinines are moderately common and dae [Shaleria (Janiomya) ornatella and S. (Shaleriella) diverse in the lower part of the succession, but the last ezerensis] occur only in high-energy environments and have species disappears in the middle Hemse beds (*middle a short range within the late Ludlow. Ludlow). Three genera are represented: Bellimurina, Pentlandina and Katastrophomena, with the species and Keywords Silurian Á Llandovery Á Wenlock Á Ludlow Á subspecies B. wisgoriensis, P. tartana, P. loveni, P. lewisii Strophomenide Á Furcitellininae Á Leptostrophiidae Á lewisii, K. penkillensis and K. antiquata scabrosa. Most of Strophodontidae Á Shaleriidae the taxa are confined to low energy environments, but P. loveni was evidently specialized for the high energy reef Kurzfassung Zwo¨lf arten Brachiopoden von der Silurium environments of the Ho¨gklint Formation. B. wisgoriensis Gotlands sind beschrieben. Sechs Furcitellininen und sechs displays environmentally induced morphological variability ,,Strophodonten‘‘. Eine Gattung ist neu; Strophodonta in developing strong, frilly growth lamellae in high-energy hoburgensis sp. n. Der Unterfamilie Furcitellininae sind auf environments. The ‘‘strophodontids,’’ although belonging Gotland ein gema¨ßigt ha¨ufiger und gering diverser to three different families, share a common morphology Bestandteil der untere teil der Abfolgen, aber die letzte Art consisting of denticles along the hinge line, a semi-circular der Unterfamilie verschwindet in den mittleren Hemse outline, unequally to finely costellate ornament and, most Schichten des mittleren Ludloviums. Die drei Gattungen importantly, a concavo-convex profile with both valves of Bellimurina, Pentlandina und Katastrophomena sind mit the same curvature, enclosing a very small body chamber. den folgenden Arten und Unterarten vertreten: B. wisgori- Two leptostrophiids are generalists, occurring in both high- ensis, P. tartana, P. loveni, P. lewisii lewisii, K. penkillensis and low-energy environments and with long stratigraphical und K. antiquata scabrosa. Die meisten Taxa sind auf ein ranges [Mesoleptostrophia filosa; latest Llandovery through niedrigenergetisches Ablagerungsmilieu beschra¨nkt, wohi- the entire Ludlow. Brachyprion (Brachyprion) semiglob- ngegen P. loveni offensichtlich auf das hochenergetische osa; latest Llandovery to latest Wenlock]. The third lep- Milieu im Bereich der Riffe der Ho¨gklint Formation spez- tostrophiid (Brachyprion (Erinostrophia) walmstedti)is ialisiert war. B. wisgoriensis weist eine milieuabha¨ngige, morphologische Variabilita¨t auf, die sich in der Entwicklung von ru¨schenartigen Wachstumslamellen unter hochenerge- O. A. Hoel Department of Earth Sciences (Palaeobiology Program), tischen Bedingungen auszeichnet. Die ,,Strophodonten‘‘, Uppsala University, Norbyva¨gen 22, 752 36 Uppsala, Sweden ho¨rt zu drei verschiedene Familien zu. Sie teilen eine gem- einsame morphologie die von der volgende bestehen: kleine Present Address: za¨hne la¨ngs die linie des Ha¨nges, eine semi sirkulares O. A. Hoel (&) Herumveien 35, 1430 A˚ S, Norway Umriss, ungleichartiger zu feiner costellate Skulptur, e-mail: [email protected] und am wichtigsten, eine konkavo-konvexes profil mit 123 202 O. A. Hoel beiden Schalen mit gleichartig Kurve, der eine sehr divided two of the species into several subspecies, although kleine Ko¨rperkammer umschliesst. Zwei Leptostrophiiden making clear that he considered most of the morphological (Mesoleptostrophia filosa und Brachyprion (Brachyprion) variation to reflect micro-environmental rather than genetic semiglobosa) sind generalisten, die im sowohl Hochenergie- causes. als Swachenergiemilieuen und durch langer stratigraphisher Members of this subfamily are relatively rare in the Intervall auftreten. Der dritten Leptostrophiid (Brachyprion Wenlock faunas of the British Isles, and this also is the case (Erinostrophia) walmstedti) hat eine ku¨rtzere stratigrafisher on Gotland. The collections in the Swedish Museum of Auftreten und tret im Swachenergiemilieuen in die spa¨testen Natural History, Stockholm, and Museum of Evolution, Llandovery auf. Die die zu den Strophodontidae (Stroph- Uppsala, contain only about 300 specimens of furcitelli- odonta hoburgensis sp.n.) und Shaleriidae (Shaleria (Jani- nines, in contrast to over 1,000 specimens of leptaenines omya) ornatella und S.(Shaleriella) ezerensis) zuho¨rt treten (Hoel 2005). The furcitellinines also have a more restricted nur im Hochenergiemilieuen auf und treten durch eine distribution than the leptaenines; Pentlandina and Belli- ku¨rzere Interwall innerhalb der spa¨tere Ludlow auf. murina occur only along the NW coast and on Stora Karlso¨, while Katastrophomena has a similar restricted Schlu¨sselwo¨rter Silurium Llandovery Á Wenlock Á distribution in the lower part of the succession. In the Ludlow Á Furcitellininae Á Leptostrophiidae Á Ludlow Hemse group, specimens are also found further Strophodontidae Á Shaleriidae Á Schweden east, but they are mainly confined to low-energy environ- ments within the western marlstone area. The geographical distribution of furcitellinine species is shown in Fig. 1, Introduction which also shows the distribution of the main facies. The stratigraphical ranges are shown in Fig. 2. The strophomenide taxa found in the Silurian succession of While the closely related furcitellinines can be mor- Gotland, Sweden, are a mix of groups that are typical of the phologically extremely variable both within and between Ordovician and groups that are characteristic of the species, several other strophomenide taxa occur in the Devonian faunas. Representative taxa of the former are the Gotland succession that belong to three different families, Strophomenidae and Leptostrophiidae, while the latter yet share a very similar morphology: This similarity con- belong to the Strophodontidae and the Shaleriidae. Some of sists of a semicircular shell shape, concavo-convex profile the species described in this article have been relatively with very narrow body cavity (the opposing valves lie very well described and figured elsewhere, mainly from the close to each other along the entire length of the animal), a British Isles, but apart from the rather cursory papers of fairly similar unequally parvicostellate radial ornament Lindstro¨m(1861) and Bassett and Cocks (1974), very few (considered to be primitive by Harper and Boucot 1978c, illustrations of Gotland material have been published. The p. 6), usually without any rugation, and development of lack of illustrations is somewhat surprising, with respect to denticles for articulation along the hinge. On Gotland, the classical status of the area, and the large amount of species of Brachyprion and Mesoleptostrophia are among papers dealing with the island’s geology. During this work, the most common and widespread brachiopod taxa. Both it was recognized that many species display quite extensive genera occur in high- and low-energy environments with- variation in morphology. I have therefore decided to out displaying much phenotypical variation attributable to illustrate each species with a larger number of illustrations environmental influences. On the other hand, the other two than has previously been usual. Hopefully this makes the fairly similar genera described here (Strophodonta and paper more useful for later studies both of the animals’ Shaleria) have a short temporal range on Gotland and are palaeobiogeography and their palaeobiology. only found in high-energy, shallow water environments. The Strophomenidae are a predominantly Ordovician group, but a few members of the subfamily Furcitellinae cross the Ordovician-Silurian boundary, and a single genus Geological setting (Katastrophomena) persists into the Ludlow (Cocks and Rong 2000). The Llandovery furcitellinine taxa of the The island of Gotland in the Baltic Sea, east of the Swedish British Isles were studied by Cocks (1968), who described mainland, forms a small, exposed part of the much larger nine nominal species and a few specimens under open area of Palaeozoic rocks comprising the bedrock of the nomenclature, belonging to six genera. From the Wenlock southern-central region of the Baltic Sea, the East Baltic of the Welsh Borderland and South Wales, Bassett (1974) states and parts of Russia and Belarus. The Silurian suc- described three furcitellinine species belonging to the cession on Gotland spans a time interval from the latest genera Pentlandina and Katastrophomena. He also noted Llandovery to the late Ludlow. During that time Gotland that the variation within each species was considerable, and was situated near the southern margin of Baltica, about 158 123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 203

Fig. 1 Map of Gotland showing main sedimentary facies and distribution of the species described herein. The distribution of Mesoleptostrophia filosa covers the entire island, and is therefore not plotted

south of the palaeoequator (Torsvik et al. 1996). Sedi- the east. The stratigraphy and depositional environments of mentation occurred on a shallow pericontinental ramp, and the succession exposed on Gotland have been studied in the rocks consist mostly of mudstones, marlstones and numerous papers, and the most useful overviews of the limestones, with some relatively minor units of sandstones. geology are those of Hede (1921, 1960), Munthe et al. Extensive reef bodies are also present at several levels of (1925), Manten (1971), Laufeld (1974), Laufeld and Bas- the stratigraphical record. The rock units dip very gently sett (1981), Bassett (1985) and Samtleben et al. (1996). (*18–28) towards the SE. At the time of sedimentation, water depth was generally greater in the SW, so that the succession is most complete in the west with about Systematic palaeontology 500 m of sedimentary succession in the SW region near Hamra, whereas there are increasingly large reef tracts, Abbreviations and repositories: GSM—Institute of Geo- unconformities and other signs of near-shore influences in logical Sciences, London; LMNH—Latvian Museum of 123 204 O. A. Hoel

Fig. 2 Stratigraphical ranges on Gotland of the species described herein. The occurrence of Shaleria (Shaleriella) ezerensis in the Slite group may be erroneous, as it is based only on the locality list in Harper and Boucot 1978b, and no specimen is figured by them from this level

Natural History, Riga; NMING—National Museum of convexity, shape of ventral muscle field, socket plates and Ireland, Dublin; PMU—Museum of Evolution, Uppsala brace plates. Their tabulation implies that their main University, Sweden; SGU—Geological Survey of Sweden, defining familial character was the shape of the ventral Uppsala; NRM—Swedish Museum of Natural History, muscle field. In contrast, Rong and Cocks (1994) used the Stockholm; USNM—US National Museum of Natural shape of the dorsal cardinalia as their key familial character History, Washington. for the non-denticulate families. They defined four types, The synonymy lists of some species would be very long, each of which supposedly characterizes a family: Type A and have therefore been reduced by including only the (Strophomenidae) has a prominent notothyrial platform, original reference and those pertaining to descriptions of the cardinal process lobes can be fused proximally and the Scandinavian material before 1977. For more complete socket ridges are curved postero-laterally, which Rong and lists see Bassett’s monographs (1971–1977). Cocks claim to be unique for this group. Type B (Rafinesquinidae) has long, discrete cardinal process lobes Class Strophomenata Williams and others, 1996 and straight socket ridges. Type C (Glyptomenidae, Folio- Order Strophomenida O¨ pik, 1934 menidae, ?Leptaenoideidae) has socket ridges fused Superfamily Strophomenoidea King, 1846 directly to the sides of the small cardinal process lobes. Family Strophomenidae King, 1846 Type D (Christianiidae) has low, fused cardinal process Classification of the strophomenides has a long history lobes and the socket ridges are developed as plates over- of discussion and conflicting opinions, and it possibly is the hanging the valve floor. These authors regard the mor- most taxonomically over-split major brachiopod group. phology of the cardinalia as being very conservative and The main differentiation has been made between the thus valid as readily defining characters for each family. It ‘‘normal’’ strophomenides with a ‘‘conventional’’ tooth and is surprising therefore to see cardinalia clearly similar to socket articulation and the ‘‘strophodontids’’ with addi- their type A rather than type C, complete with curved tional denticulate structures along the hinge line. Harper socket ridges in Glyptomena, the presumably most typical and Boucot (1978a, b, c, pp. 60–61) recognized ten fami- Glyptomenid (see Cocks and Rong 2000, Fig. 156). In fact, lies within the ‘‘Strophodontacea’’ based on ornament, most of the genera assigned to Glyptomenidae figured by 123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 205

Cocks and Rong (2000, Figs. 156–159) have cardinalia and Llandovery of Europe and North America. I agree that the dorsal muscle fields very similar to those assigned to morphology is so similar that a close phylogenetic rela- Strophomenidae (Cocks and Rong 2000, Figs. 135–145). tionship is probable, although the temporal distribution of Their types A and C differ in reality only in the relative the genus thereby becomes discontinuous. The difference size of the cardinal process lobes. Since both the proximal between the two subgenera is defined such that B. ends of the cardinal process lobes and the proximal ends of (Bellimurina) has continuous dorsal transmuscle ridges and the socket ridges are contiguous with the notothyrial plat- a low peripheral rim in the dorsal valve, whereas B. form in both types, it is somewhat a matter of definition as (Cyphomenoidea) has vestigial dorsal transmuscle ridges to whether the socket ridge actually contacts the cardinal and a high peripheral rim. In my opinion these small process lobe or not. The cardinalia of Leptaenoidea (Hoel morphological differences between the subgenera make 2007) seem to be similar to the Type C in having socket splitting within the genus unnecessary. A similar degree of ridges in contact with the cardinal process lobes through all variation is found even within populations of B. visgori- their height, but the notothyrial platform is well developed, ensis described below from the lower Visby Formation of with a strong median ridge reaching far forward in the Gotland. The variation there seems to correlate with mantle cavity, as in Type A. Most other characters of growth; although some large specimens lack the rim (see Leptaenoidea are also consistent with a close relationship Fig. 3Z), the specimens with the highest peripheral rim are with the subfamily Furcitellinae within the Strophomeni- usually also the largest and most gerontic, with the most dae (Hoel 2007). For the denticulate families, Rong and elevated muscle scars (see Fig. 3P), where any transmuscle Cocks (1994) followed Harper and Boucot (1978a, b, c) ridges are effaced. It thus appears that these two distin- quite closely, although reducing the number of families to guishing characters are dependent only on the ontogenetic seven. In these groups, they defined three types of cardi- development of the specimen in question. The separation nalia, but did not attach much confidence to them as of Bellimurina into subgenera is therefore not followed in defining characters. They considered instead the shape of this paper. the ventral muscle field to be a conservative feature, although they did not discuss why the ventral muscle field Bellimurina wisgoriensis (Lamont and Gilbert, 1945) should be a more conservative structure in the ‘‘stroph- (Fig. 3) odonts’’ than in the non-denticulate stocks. However, they argued that the narrow space between the valves hindered v.1916 Rafinesquina(?) sp.—Holtedahl: 31, pl. 3, Fig. 6 evolutionary development of the cardinalia. Supposedly v*1945 Leptaena wisgoriensis—Lamont & Gilbert: 660, this is the reason why the cardinal process was such a pl. 3, Figs. 10–14 conservative feature in most strophomenata, but it does not v.1951 Leptaena wisgoriensis Lamont & Gilbert.— explain why even the denticulate families in fact show Williams: 119 dramatic evolution of the cardinalia (see, e.g., Williams v.1968 Cyphomena (Cyphomenoidea) wisgoriensis 1953), especially because many of these brachiopods did (Lamont & Gilbert).—Cocks: 316, pl. 12, have extremely narrow space between the valves.The work Figs. 9, 10, 11, 12 of Rong and Cocks (1994) (and by extension that of Cocks v.1968 Bellimurina sp.—Cocks: 321, pl. 14, Figs. 9–10 and Rong 2000) can be said to have been a step forward in v.1978 Cyphomena (Cyphomenoidea) wisgoriensis stating more clearly what characters the classification was (Lamont & Gilbert).—Cocks: 119 based on, but the characters used in the definitions are v.1982 Cyphomenoidea wisgoriensis (Lamont & probably still too few and too variable: A comprehensive Gilbert).—Thomsen & Baarli: pl. 3, Figs. 9, 11, 12 cladistic analysis of the Strophomenida is required in order v.1995 Cyphomenoidea wisgoriensis (Lamont & to elucidate many of the relationships that would lead to a Gilbert).—Baarli: 40, pl. 13, Figs. 12–23 more compatible classification, but is beyond the scope of the present paper. Material: About 50 specimens; conjoined valves, ventral Subfamily Furcitellinae Williams, 1965 and dorsal interiors from the lower and upper Visby For- Genus Bellimurina Cooper, 1956 mation and the Ho¨gklint Formation. Description: Shell semi-rectangular to transverse, about Type species: By original designation; Leptaena 60% as long as wide, with the maximum width mostly charlottae Winchell & Schuchert, 1892, p. 288. anterior to the hinge line at about mid length. Ventral valve Remarks: Cocks and Rong (2000) differentiated between more or less evenly convex, with the dorsal valve flat to two subgenera, Bellimurina (Bellimurina) from the Caradoc slightly concave and with a weak, short geniculation in the of North America and B.(Cyphomenoidea) from the late anterior third. 123 206 O. A. Hoel

Ventral beak prominent, extending beyond the hinge Fig. 3 Bellimurina wisgoriensis (Lamont & Gilbert, 1945). Scale bar c line and bearing an open, permesothyrid foramen. 1 cm. A–C NRM Br 35380, conjoined valves with slight genicula- tion, ventral, dorsal and lateral views; lower Visby Formation, Pseudodeltidium relatively large, occupying about 10% of Norderstrand, Visby; D–E NRM Br 123656, conjoined valves, dorsal, the hinge width and about 75% of interarea height. The posterior and ventral views; Galgberget, Visby; F–H NRM Br height of the ventral interarea is slightly less than 10% of 138064, small dorsal valve, posterior, dorsal and ventral views; the hinge width. Dorsal interarea very low, notothyrium as Ireviken 2, Stenkyrka; I, M NRM Br 123693, dorsal valve, posterior and dorsal views; Visby, old collection; J–L, N NRM Br 123692, wide as the pseudodeltidium, and with a prominent dorsal valve, frontal, dorsal, posterior and ventral views; Visby, old chilidium covering the proximal part of the cardinal collection; O–Q NRM Br 35376, dorsal interior, ventral, posterior process lobes. and lateral views; upper Visby Formation at Bla˚ha¨ll, Tofta parish; The shell has a characteristic sculpture of low, sharp R–S, V NRM Br 123649; Ventral interior in views perpendicular to the commisure, the interarea and parallel to the interarea; lower Visby rugae deflected forwards where they are crossed by the Formation, Norderstrand; T NRM Br 123689, small dorsal valve costae. The costellae do not make any impression on the interior; Galgberget, Visby; U NRM Br35381, dorsal interior view; rugae. The concentric ornamentation also involves growth lower Visby Formation, Norderstrand; W–Y PMU G1058, conjoined interruptions where the mantle has retracted before valves with frilly lamellar growth; Visby Formation, unknown locality; Z NRM Br 123650, dorsal interior with exterior sculpture continuing growth below the former commisure line. This highly visible; lower Visby Formation, Norderstrand; Aa–Ab PMU interrupted pattern is repeated at shorter and shorter inter- G1059, dorsal interior, ventral and posterior views; Visby Formation, vals as the animal approaches full size and this results in a unknown locality frilly valve surface. Most specimens show two or three more pronounced growth lines where the growth of the cardinalia are stout, supported on a short, elevated noto- valves ceased briefly. thyrial platform. Cardinal processes are relatively long and Ventral interior: Delthyrial cavity deep below the tubular, diverging about 15–30°; their muscle attachment pseudodeltidium, without any visible callist. Teeth widely facets are oval and posteriorly directed, their proximal divergent, ridge-like to subtriangular in dorsal view, with parts covered by the small chilidium. The sockets are deep numerous small ridges perpendicular to the hinge line and trough-like, with their open end angled posteriorly. along the posterior side, and supported by wide dental Socket plates are quite thick, curving slightly, fused plates, which are continuous with the muscle bounding posteriorly with the notothyrial platform, and diverging at ridges at their frontal edge. The muscle field is round to about 1208. Muscle field is elevated, bisected longitudi- diamond-shaped; the posterior part is slightly depressed, nally by a wide, convex ridge, which is fused to the but most of the field is elevated well above the valve notothyrial platform posteriorly and is forked anteriorly. floor, surrounded by high muscle bounding ridges that Posterior end of each adductor scar is a deep, crescent- overhang the valve floor and almost meet anteromedially. shaped pit bounded posteriorly by the notothyrial platform, The adductor scars are relatively small, set in the extreme while the scars themselves are set on the broad transmuscle posterior of the delthyrial cavity, extending forwards as septa, which diverge anterolaterally at about 458. Each far as half of the muscle field length. Diductor scars tri- transmuscle septum is composed by two parallel subsepta; angular and elongated, with width about half the height of the lateral subseptum is well elevated above the floor of the the muscle bounding ridge. The muscle scars are valve, while the medial subseptum is slightly lower and separated by a thick, rounded median ridge, which continues forwards as a narrow curved ridge enveloping the increases in height forwards and in some specimens frontal scars, but they do not meet medially. The extra- continues well in front of the muscle field, and is raised muscular area is covered with extremely small ridges and as a high, cutoff knob at the frontal end of the muscle pustules, and the external ornament is clearly visible on the field (Fig. 3R, V). The extramuscular area close to the inside. There are no visible vascular traces in the dorsal muscle field is covered in very small pustules less than valve. 0.05 mm in diameter, but further frontally the pustules disappear and the surface is almost smooth. The vascula Remarks: Most of the specimens from the lower Visby media extend from the anteromedial end of the muscle Formation in the NRM museum collections previously field as two quite wide troughs with slightly elevated identified as Pentlandina belong to B. wisgoriensis.This edges. The troughs then bifurcate two or three times as species can be distinguished easily from the specimens of they approach the valve margin, where they occupy only Pentlandina tartana (see below), which co-occurs at the anterior half of the commisure line. Norderstrand, Visby; B. wisgoriensis is usually much Dorsal interior: The disc is surrounded by a bounding larger, and it has a strong zig-zag rugae pattern, frilly ridge, which can be quite high (Fig. 3P), or by several lamellose growth lines, and usually more pronounced successive low bounding ridges coinciding with the major growth ridges; the specimens also lack the fold and sulcus halts in shell growth seen on the outside of the valve. The of Pentlandina. In the Ho¨gklint Formation, the specimens 123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 207

123 208 O. A. Hoel are generally larger and have a stronger sculpture, with to the horizontal of around 458. Ventral umbo low; some- more frequent and distinct growth reversals of the anterior times a very small, open apical foramen is visible. Ventral margin, resulting in more frilly appearance. interarea relatively high, delthyrial angle 808. Pseudo- deltidium small, only half as high as the width of the Distribution: B. wisgoriensis occurs in the lower and interarea; chilidium of equal size as the pseudodeltidium, upper units of the Visby Formation and in the Ho¨gklint both narrow, occupying about 1/8 of the length of the hinge Formation, from Gnisva¨rd in the SW to Irevik in the NE. line. Radial sculpture parvicostellate, main costellae thin, Norwegian specimens belonging to this species were with 8–10 smaller fila in the interspaces. Concentric sculp- described by Baarli (1995) from the top of the Ryttera˚ker ture consists of very small growth lines, sometimes produced Formation and base of the Vik Formation. These are of into small rugae, which are deflected into zig-zags when middle Telychian (C4) age (Worsley et al. 1983), and thus crossing the costellae. Most specimens also have 2–3 growth slightly older than the British specimens described by ridges, which are mostly developed near the shell margin. Cocks (1968), which is of C age. A few specimens were 5 Remarks: This species differs from P. lewisii (see also found by me in the lower part of the Braksøya For- below) in having a small pseudodeltidium, covering only mation (lowermost Wenlock) on Storøya, Ringerike, Nor- the apical part of a wide delthyrium (in P. lewisii, the way. These specimens display almost only the concentric delthyrium is narrower and the pseudodeltidium covers the ornamentation, and no radial costellae, which makes the entire height of it), less accentuated costellae, smaller size, shell seem incredibly wrinkled. and much stronger development of the fold and sulcus. In the British Isles it is recorded from the latest Llan- dovery of Worcestershire, but may be present also in Distribution: On Gotland, P. tartana is only known from Shropshire (Cocks 1968, p. 317). the lower Visby Formation (latest Telychian) immediately north of Visby. Genus Pentlandina Bancroft, 1949 In the British Isles, it is known from the Pentland Hills, Type species: Strophomena (P.) tartana Bancroft, 1949, Scotland, and possibly from the Tortworth Inlier, Welsh p. 13; OD. Borderland; both occurrences are of latest Telychian age. A somewhat similar species is present in the Ningqiang Pentlandina tartana Bancroft, 1949 (Fig. 4) Formation (late Telychian) of north Sichuan, China (see Bassett and Rong 2002, p. 134, Fig. 92B, C). In that paper, the figured specimen is identified as P. cf. lewisii (David- v.1866 Strophomena antiquata (J. de C. Sower- son), but apart from having the same geological age as by).—Davidson: 17, pl. 2, Figs. 21–23 P. tartana, it also seems to have a similar tall fold and v.1871(part) Strophomena antiquata (J. de C. Sower- sulcus, and the same strong zig-zag pattern in the con- by).—Davidson: 299, pl. 44, Figs. 7–9 only centric ornament as the latter species. v*1949(part) Strophomena (Pentlandina) tartana [Lamont MS].—Bancroft: 13, non pl. 1, Fig. 10 Pentlandina loveni (de Verneuil, 1848) (Fig. 5A–T) v.1968 Pentlandina tartana Bancroft.—Cocks: 289, pl. 1, Figs. 1–6 v*1848 Leptaena loveni—de Verneuil: 339, pl. 4, Fig. 5 v.1974 Pentlandina sp.—Bassett & Cocks: 14 v.1861 Strophomena loveni (de Verneuil).—Lindstro¨m: 371 Material: Eighteen specimens, all conjoined valves from v.1968 Pentlandina loveni (de Verneuil).—Cocks: 289 the lower Visby Formation just north of Visby. All speci- v.1974 Pentlandina loveni (de Verneuil).—Bassett & mens were probably found loose in beach gravel and are Cocks: 14, pl. 2, Figs. 4–6 quite strongly worn, almost obliterating the outer surface in some specimens. Type material: Lectotype—University of Orsay D653, the complete shell figured by de Verneuil on his pl. 2, Description: Outline semicircular to transversely sub- Fig. 5a; assigned and refigured by Bassett and Cocks rectangular, usually about 60% as long as wide. Ventral (1974, pl. 2, Fig. 5a–c), who also figured the two syntypes valve initially convex at the umbo, but after the first major of de Verneuil (1848, pl. 4, Fig. 5b, c (D652), and Fig. 5d growth line (at around 25–30% of adult length), a deep (D654)). sulcus develops in the ventral valve, with a corresponding fold in the dorsal valve. In some specimens this folding is so Description: Shell small, length about 8 mm, rarely up strong that the anterior commisure is vertical on both sides to 15 mm. Outline usually rounded square to almost of the median line, but usually the commisure has an angle circular, but is often irregular. The widest point is usually

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 209

Fig. 4 Pentlandina tartana Bancroft, 1949; Conjoined valves, lower lateral views; D–E NRM Br 48921; posterior and ventral views; Visby Formation, Norderstrand, Visby. Scale bar 1 cm. A–C, F–H I–L NRM Br 123648; posterior, ventral, dorsal and anterior views NRM Br 102553; ventral, dorsal, anterodorsal, posterior, anterior and at about 30% of final length, but can also be at the hinge muscle bounding ridges. Muscle field triangular, in some width. The profile is concavo-convex to biconvex, with a specimens rectangular, elevated above the valve floor, deep, rounded ventral valve and a flat to convex dorsal strongly so in gerontic specimens. Adductor and diductor valve, often with a ventrally directed furrow followed scars of equal width, each muscle occupying 20% of the immediately by a sharp dorsal geniculation in the antero- muscle area width; the anterior 20% is occupied by a low, medial part of the dorsal valve. Frontally, there is usually a wide median ridge, which separates the right and left very strong fold and sulcus developed, but in some speci- adductors. The anterior end of this ridge is elevated into a mens, this structure is not developed at all. Ventral beak is knob, then it drops vertically to the valve floor and con- erect, with an open apical foramen. Dorsal beak incon- tinues a short distance anteriorly, bounded on both sides by spicuous, but visible as a small knob. Ventral interarea a vascular trace, before blending into the valve floor at wide, with clear horizontal growth lines, its triangular about mid-length of the valve. The valve floor is covered shape distorted where the shell developed growth ridges; by very small taleolae arranged radially. Pseudodeltidium strongly vaulted and high, reaching Dorsal interior: Even in rather flat valves, the interior almost to the hinge line, relatively wide, occupying surface is bowl-shaped and relatively deep. A bounding between 1/3 and 1/5 of hinge line width. Dorsal interarea ridge around the disc is often developed, making the interior much narrower than the ventral area, of subequal width out relatively more spacious than in most strophomenides. to the lateral margins of the hinge line; chilidium low but Cardinalia elevated on a strong, anchor-shaped notothyrial convex, relatively narrow, occupying about 1/6 to 1/10 of platform. Cardinal process lobes strong and elevated, hinge width, covering most of the cardinal process lobes, muscle attachment areas directed posteriorly, but in some but in-folded between them. Concentric sculpture near the specimens they point up to 308 laterally as well. Sockets apex of both valves comprises small growth lines, in the deep and trough-like, bounded anteriorly by strong socket more distal part of the shells there are usually strong, zig- ridges growing anterolaterally with an angle of 15–208 to zag shaped rugae; periodical mantle retractions resulted in the hinge line. The adductor muscle scars are rounded and several growth ridges in many specimens, but they are deeply impressed posteriorly and divided by the anterior usually not as strong, nor as numerous as in Bellimurina extension of the notothyrial platform, which bifurcates at visgoriensis (see above). Radial sculpture consists of very half the length of the muscle field, producing a deep median thin costellae which interrupt the rugae; in the interspaces trench. The anteromedian scars are supported by this there are 4–5 thin fila. bifurcated median ridge, while the posterolateral muscle scars are supported by blade-like extensions of the muscle Ventral interior: Delthyrial cavity deep, roofed over by field, which overhang the valve floor. From the anterior the pseudodeltidium. Teeth strong, triangular, supported ends of the anteromedian scars, paired ridges develop, by strong dental plates, which blend seamlessly into the

123 210 O. A. Hoel

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 211 b Fig. 5 A–T Pentlandina loveni (de Verneuil, 1848); all from the loveni, this may suggest a habitat of current-swept hard Ho¨gklint Formation, note open apical foramina and irregular shape. ground. Scale bar 1 cm; A–D NRM Br 35445, unknown locality; ventral, lateral, dorsal and frontal views; E–H NRM Br 35442, unknown Distribution: P. loveni is known with certainty only locality; ventral, lateral, frontal and dorsal views; I–K NRM Br from Gotland, where it occurs in the early Wenlock 123673; ventral valve, exterior, interior and posterior views; L, M NRM Br 123676, unknown locality; dorsal valve, posterior and Ho¨gklint Formation and coeval beds assigned to the middle interior views; N, O NRM Br 123675, unknown locality; dorsal valve, Slite group on Fa˚ro¨. interior and posterior views; P, Q NRM Br 123685, Galgbacken, Visby; small, globular ventral valve, exterior, interior and posterior Pentlandina cf. lewisii (Davidson, 1847) (Fig. 5U, V) views; R PMU G1062, Lickershamn, Stenkyrka; very small dorsal valve with a larval shell attached to its inner surface; S, T NRM Br Remarks: Two small specimens were found in the Slite 123686, Galgbacken, Visby; large ventral valve with strong fold, interior, posterior and lateral views. U–Af Pentlandina lewisii lewisii group at Slite (NRM Br 136067; not figured) and NRM Br (Davidson, 1847); conjoined valves. Scale bar 1 cm. U–W NRM Br 138066 (Fig. 5U, V) from the Klinteberg Formation at 102614, Slite group, Va¨stergarn, Sanda; dorsal, frontal and posterior Klinteberg. They are similar to P. loveni in having a large views; X–Z NRM Br 102616, Slite Group, Va¨stergarn, Sanda; open apical foramen and also have a ventral muscle field ventral, frontal and posterior views; Aa, Ab NRM Br 35658, upper Visby Formation, Gnisva¨rd, Tofta; dorsal and frontal views; Ac–Af: quite similar to small specimens of the latter species (e.g., NRM Br 123532, Slite Group, Valbytte, Sanda; posterior, frontal, Fig. 5P). Their shell ornamentation is more similar to that dorsal and ventral views. Ag–Ah Pentlandina cf. loveni (de Verneuil, of P. lewisii lewisii (e.g., Fig. 5Ae), but the ventral muscle 1848); NRM Br 138066, incomplete ventral valve with large foramen, field of that species is quite different, as can be seen in Klinteberg Formation, Hunninge 1, Klinte; exterior and interior views Bassett (1974, pl. 25, Figs. 14, 15). In my view, these specimens are evolutionarily intermediate between the two which swing anteromedially to enclose the anterior scars, species (at least the one from Klinteberg), possibly closer but do not merge medially. A thin median septum originates to P. lewisii (on stratigraphic criteria), but lived in higher within the trench of the bifurcated median ridge and con- energy environments than the other known specimens and tinues forwards between the paired ridges to about 66% of retained pedicular attachment into adulthood. the valve length, then blends into the valve floor. No clear vascular traces are present, but the valve floor is covered in Pentlandina lewisii lewisii (Davidson, 1847) (Fig. 5W–Ah) very small taleolae arranged radially, as in the ventral valve. In young specimens, the exterior sculpture is visible on the v*1847 Leptaena lewisii—Davidson: 59, pl. 12, inside of the valves, but is obliterated by secondary shell FigS. 22–24 thickening in gerontic individuals. v.1848(part) Leptaena antiquata (J. de C. Sowerby).— Davidson: 319 pars, pl. 3, Fig. 11 right hand Remarks: Small specimens of P. loveni can be difficult to fig., non left hand fig., non J. de C. Sowerby distinguish from B. visgoriensis, but differ by having more in Murchison, 1839 anteriorly directed socket ridges, usually more erect cardi- v.1871(part) Strophomena antiquata (J. de C. nal process lobes, and the ridges on both sides of the anterior Sowerby).—Davidson: 299, pl. 44, Figs. 3, scars enclose the scars rather than expand forwards as in 3a, non Figs. 2, 4–13, 21, 22, non J. de C. B. visgoriensis. On the exterior, the two species have similar Sowerby in Murchison, 1839 ornaments, but the strong growth ridges of B. visgoriensis v.1916 Strophomena loveni (de Verneuil).— are usually not found in small specimens of P. loveni. Holtedahl: 60, pl. 13, Fig. 5 Specimens of this species from the Ho¨gklint Formation v.1949 Strophomena (Pentlandina) aff. tartana are commonly markedly asymmetrical. Some groups of [Lamont MS].—Bancroft: p. 13 shells occur in tight clusters, each apparently attached to v.1968 ?Pentlandina lewisii (Davidson).—Cocks: other shells of the same species (e.g., NRM Br 35395, 289 [reference to species only, questionably unfigured). The limited space for growth results in the assigned to Pentlandina] asymmetrical shape. Such gregarious behavior is well known v.1974 Pentlandina sp.—Bassett & Cocks: 14 in living brachiopods. Studies on modern faunas have [reference to specimens found on Gotland revealed that the orientation of individuals in crowded and with tentative assignment to species] clustered populations are quite random, and individuals in v.1974 Pentlandina lewisii (Davidson).—Bassett: the populations observed show no reorientation in response 101, pl. 25, Figs. 10–16, pl. 26, Figs. 1–3 to currents. In this case, stability seems to be of greater importance in determining orientation than the direction of Material: 28 conjoined valves from the Slite group, one water flow (Richardson 1997, p. 451). For Pentlandina conjoined specimen from the upper Visby Formation.

123 212 O. A. Hoel

Remarks: This species was described by Bassett (1974), Ventral interarea relatively low, about 5% of hinge width. and the Gotland specimens do not exhibit any marked Delthyrium wide, usually covered only apically by a small differences from the British material, except in having a pseudodeltidium, but some specimens have a pseudo- ventral interarea that has more even width along the whole deltidium that covers the whole delthyrium. Dorsal hinge line and a less frilly appearance of the costellae interarea much lower than the ventral area, with a small where they are crossed by the concentric growth lines. chilidium covering only the proximal parts of the cardi- nalia. Radial ornament finely parvicostellate, with thin Distribution: On Gotland, the species is known from a costellae with 4–5 very fine fila in the interspaces, from single specimen in the upper Visby Formation at Gnisva¨rd, some of which new costellae gradually arise. Concentric and more commonly in the western part of the middle Slite ornament of fine growth lines, some specimens display two group (late Sheinwood) around Va¨stergarn and on Stora or three strong growth ridges, indicating periodic cessation Karlso¨. This region had a rather low-energy sedimentary of growth. A very few specimens (Fig. 6A, G) exhibit environment. irregular rugae, which are deflected when crossing a In Norway only two specimens are known (Holtedahl costella, creating a zig-zag pattern similar to that of 1916, pl. 10, Fig. 9; pl. 13, Fig. 5) from the basal part of Bellimurina (see above). the Malmo¨ya Formation (middle Wenlock, coeval with the Ventral interior: Delthyrial cavity deep, roofed over by base of the Slite group on Gotland). In the specimen PMO the pseudodeltidium. The innermost part is filled by the L-139 (Holtedahl 1916, pl. 13, Fig. 5), the ornamentation is posterior part of the median ridge of the muscle field, more or less identical to that of the holotype of P. lewisii which here has a median depression and extends to the plakodis Bassett (1974, pl. 26, Fig. 4c). apex of the shell, obliterating the inner end of the apical In the British Isles, it is known only from rare occur- foramen. The teeth are relatively small and bluntly trian- rences in the Wenlock shale and Limestone in Shropshire, gular, with vertical striations on their posterior face. Dental Dudley and Walsall. plates blend smoothly into the muscle-bounding ridges. Genus Katastrophomena Cocks, 1968 Ventral muscle field round to diamond-shaped, with L/W Katastrophomena (Katastrophomena) penkillensis ratio from 0.65 to 0.85. The adductor scars occupy the (Reed, 1917) (Fig. 6) anterior half of the muscle field, on both sides of the median ridge; their width is about 33% of the width of v.1916 Strophomena antiquata (J. de C. Sowerby).— the muscle field. The muscle bounding ridges do not meet Holtedahl: 58, pl. 10, Fig. 10 anteriorly, but are deflected forwards on both sides of the v*1917 Strophonella penkillensis—Reed: 900, pl. 18, median ridge for a short distance anterior to the muscle Figs. 11–14 field. The extra-muscular area is covered with very small v.1968 Katastrophomena penkillensis Reed.—Cocks: taleolae, slightly larger ones occur close to the muscle 297, pl. 4, Figs. 1–6 field; vascular traces are rarely present, but some speci- v.1974 Katastrophomena sp.—Bassett: 110, pl. 28, mens (e.g., Fig. 6E) preserve bifurcating mantle canals Fig. 12 close to the margin. Dorsal interior: The cardinalia are raised on a short, Description: Exterior: Shell outline rounded triangular high notothyrial platform. Cardinal process lobes stout, with the maximum width usually at the hinge line, but tubular and posteriorly directed, with strong striation on the sometimes slightly anterior to this. The lateral margins of muscle attachment facets. Socket plates strong, fused with the hinge line are normally produced as quite sharp alae. the notothyrial platform, curving anterolaterally then lat- Shell length usually about 60–70% of width, but in some erally, diverging about 1458 from one another; the crest of specimens the L/W ratio approaches 1/1. Initially the the socket plate curves ventroposteriorly around the socket, ventral valve is weakly convex, but then becomes resupi- making the socket into a half-pipe shaped trough with its nate, and the growing edge is deflected weakly ventrally to opening towards the rear of the animal. Muscle field deeply produce a gently concave ventral disc. The dorsal valve is impressed posteriorly; the muscle scars are separated by a initially weakly concave or flat, but becomes weakly con- rounded median ridge produced anteriorly from the noto- vex during growth; at about half length a more strongly thyrial platform, and which bifurcates anteriorly. A thin ventral deflection occurs, making the valve quite strongly median ridge originate at the front of the adductor scars. convex. The commisure is mostly in a single plane, but Each lateral adductor scar is rounded posteriorly, and the with a slight dorsal fold anteromedially. Dorsal umbo is anterior part of each becomes rectangular and blade-like low and inconspicuous, ventral beak erect, often having a during ontogeny; the anterolateral ends overhang the valve small foramen open on the outside, but plugged internally. floor. A thin groove separates the lateral from the median

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 213

Fig. 6 Katastrophomena penkillensis (Reed, 1917). All from the healed shell damage; E, H NRM Br 138200; ventral interior with upper Visby Formation at Gnisva¨rd, Tofta unless otherwise indicated. particularly strong mantle canals, dorsal and posterior views; F NRM Scale bar 1 cm. A NRM Br 35612, Ho¨gklint Formation, Visby; Br 138199b; dorsal interior, note the indented lateral shell margin; ventral valve with particularly well-developed rugae; B, D, G NRM I, K NRM Br 138199a; dorsal interior in ventral and posterior views; Br 35559; frontal, posterior and ventral views, note repaired hole in J NRM Br 35566, Ho¨gklint Formation, Medebys, Hall; ventral view, shell; C NRM Br 35637a; ventral view, note the enormous area of note several instances of shell repair adductor scar; the median scar is narrow and short, the lateral adductor scars, is covered with minute pustules. The ridge on which it is placed continues forwards to become a muscle scars are smooth or have impressions of the muscle long, high, sinuous ridge, which encloses the anterior scars fibers. There are no clear vascular traces, but the surface and then bends laterally to blend into the valve floor. The near the commisure has short, regular grooves perpendic- entire valve interior, except the surface of the median and ular to the valve edge.

123 214 O. A. Hoel

Remarks: These Gotland specimens are assigned to K. v.1871(part) Strophomena antiquata (J. de C. penkillensis on the basis of the sculpture of unequally sized Sowerby).—Davidson: 299, pl. 44, Figs. 6, costellae, but as the preservation is different from the 10–13, non Figs. 2–5, 7–9, 21, 22, non J. de British specimens figured by Cocks (1968), they are not C. Sowerby in Murchison, 1839 easy to compare. The overall shape is quite similar, but the 1949 Strophomena scabrosa (Davidson).— dorsal muscle field seems to be more strongly developed in Bancroft: 13, pl. 1, Figs. 12–15 the Gotland specimens, especially the anterior paired ridges v.1949 Strophomena dura—Bancroft: 15, pl. 1, in front of the muscle scars. Apparently the convexity of Fig. 11 the dorsal valve is also greater in the Gotland material. v.1968 Katastrophomena scabrosa (Davidson).— A closely similar form is the specimen figured by Bas- Cocks: 293 [reference to name only] sett (1974, pl. 28, Fig. 12) from the lower Wenlock of v.1968 Katastrophomena dura (Davidson).— Sawdde Gorge, Carmarthenshire, which has similar Cocks: 293 [reference to name only] sculpture and shape of the ventral muscle field, and also v.1974 Katastrophomena scabrosa (Davidson).— similar long triangular outline. Bassett & Cocks: 13 The shells are often damaged during growth, resulting in v.1974 Katastrophomena antiquata scabrosa (Dav- areas with abnormal ornamentation, usually very subdued idson).—Bassett: 107, pl. 27, Figs. 9–12, pl. radial sculpture and more pronounced growth lines. One of 28, Figs. 1–6 the specimens (Fig. 6C) apparently lost and regrew more than half of its shell. Another (Fig. 6G) repaired a hole Remarks: This subspecies was described in detail by punched through the dorsal valve within the visceral area. Bassett (1974) together with K. antiquata antiquata (J. de C. Sowerby, 1839). Bassett (1974) found that the only differ- Distribution: On Gotland, the species is known from the ence between the two named subspecies and further speci- lower and upper Visby Formation, the Ho¨gklint Formation, mens described by him under open nomenclature was in the and the Slite marl around Klintehamn in the SW part of the degree of ornament development. He therefore suspected Slite group. that they all belong to the same, widely variable species, but In Norway, it is known only from the single specimen refrained from putting them in synonymy pending better figured by Holtedahl (1916, pl. 10, Fig. 10), which comes collections. The specimens from Gotland usually are similar from the probably latest Llandovery Bruflat Formation of to K. antiquata antiquata in having a more transverse, Storøya in the Ringerike District. Deposition here was in a semicircular outline rather than the subtriangular outline of quiet, muddy environment below the normal wave base K. antiquata scabrosa, but the ornament is similar to that of (see Worsley et al. 1983, p. 27), which was quite similar to the latter subspecies. Specimens from the high-energy the environment of the Visby Formation on Gotland. environments of the eastern Slite group and the Klinteberg In the British Isles, the species occurs in the uppermost Formation have costellae that are strong, tightly packed and Llandovery of Ayrshire (Scotland) and Shropshire (Cocks frilly, while specimens from the lower energy environment 1968). It is probably also present in the lower Wenlock of of the Hemse group have more widely spaced costellae, as Sawdde Gorge, Carmarthenshire (Bassett 1974). seen in the specimens referred to as K. antiquata subsp. B by Bassett (1974, pl. 28, Figs. 10, 11). Katastrophomena (Katastrophomena) antiquata scab- K. antiquata scabrosa can be distinguished from rosa (Davidson, 1847) (Fig. 7) K. penkillensis (Reed, 1917) from the Visby-Slite units (see above) by its semicircular outline and much coarser radial v*1847 Orthis scabrosa—Davidson: 61, pl. 13, ornament. In the dorsal interior the difference between the Figs. 14, 15 species is quite pronounced in the adductor muscle scars; v.1848 Leptaena scabrosa (Davidson).—Davidson: K. penkillensis has very wide lateral adductor scars and 318, pl. 3, Fig. 13 very narrow medial adductor scars, whereas K. antiquata v.1848(part) Leptaena antiquata (J. de C. Sowerby).— scabrosa has narrow lateral adductor scars and wide medial Davidson: 319, pl. 3, Fig. 11 left hand fig., adductor scars. non right hand fig., non J. de C. Sowerby in Murchison, 1839 Distribution: The species is known from the easternmost v.1848 Strophomena scabrosa (Davidson).— end of the late Sheinwood Slite group at Slite, in the latest D’Orbigny in Davidson: 336 [name only] Wenlock Klinteberg Formation at Klinteberg and Lilla v.1861 Strophomena scabrosa (Davidson).— Karlso¨, and in the western part of the lower Hemse group Lindstro¨m: 372 [name only] (early Ludlow) from Petesvik to Sandarve.

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 215

Fig. 7 Katastrophomena antiquata scabrosa (Davidson, 1847). Scale Solklint 1, Othem; exterior and two interior views of dorsal valve with bar 1 cm. A–C NRM Br 35374, Hemse group, Stenbro A˚ , Othem; unusual, circular outline; K, L NRM Br 114780, Hemse group, conjoined valves in dorsal, ventral and posterior views; D NRM Br Petesvik, Hablingbo; posterior and ventral views of incomplete dorsal 35589, Hemse Group, Petesvik, Hablingbo; small conjoined valves, valve; M NRM Br 35568, Klinteberg Formation, Klinteberg, Klinte; ventral view; E NRM Br 35569, Klinteberg Formation, Klinteberg, ventral interior; N, O NRM Br 35372, Hemse group, Stenbro A˚ , Klinte; ventral view of conjoined valves; F, G NRM Br 35369, Othem; posterior and dorsal views of ventral interior; P, Q NRM Br Hemse group, Petesvik, Hablingbo; incomplete conjoined valves, 114779, Hemse group, Petesvik, Hablingbo; dorsal and posterior dorsal and posterior views; H–J NRM Br 138065, Slite group, views of incomplete ventral valve

In the British Isles, it occurs in the Wenlock Limestone Mesoleptostrophia (Mesoleptostrophia) filosa (J. de C. of Benthall Edge, Dudley, Sedgley, Walsall and the May Sowerby, 1839) (Fig. 8) Hill Inlier, and the ‘‘Lower Ludlow Shale’’ of Dudley and Sedgley (Bassett 1974, p. 109) v*1839 Orthis filosa—J. de C. Sowerby in Murchison: 630, pl. 13, Fig. 12 Family Leptostrophiidae Caster, 1939 v.1846 Orthis filosa J. de C. Sowerby.—M’Coy: 30 Genus Mesoleptostrophia Harper & Boucot, 1978 v.1847 Orthis filosa J. de C. Sowerby.—Davidson: 62, Subgenus Mesoleptostrophia (Mesoleptostrophia) pl. 13, Fig. 24 Harper & Boucot, 1978 1848 Leptaena filosa (J. de C. Sowerby).—Davidson: 318, pl. 3, Fig. 9 Type species: By original designation; M. kartalensis 1848 Strophomena filosa (J. de C. Sowerby).—Phillips Harper & Boucot nom. nov. pro Stropheodonta (Lepto- & Salter: 380 strophia) explanata Paeckelmann & Sieverts, 1932, non 1861 Strophomena filosa (J. de C. Sowerby).— Sowerby, 1842 in 1840–1846, p. 40. The type species is Lindstro¨m: 373 from the lower Devonian of Turkey. 123 216 O. A. Hoel

Fig. 8 Mesoleptostrophia (Mesoleptostrophia) filosa (J. de C. Sow- Hablingbo; J, J* NRM Br36086. Complete and detail view of dorsal erby, 1839). Scale bar 1 cm, except in figures I*, J* and valve; Hamra or Sundre Fm., Gervalds, Vamlingbo; K, K* NRM K* = 0.5 cm. A, B, E–G NRM Br35697; posterior, anterior, lateral, Br129894. Group and detail view of small, but robust dorsal valve; ventral and dorsal views of conjoined valves; Hemse group, Sandarve Hemse group, Ringome, Alva; L NRM Br36088; Ventral valves; kulle, Fardhem; D NRM Br36095. Ventral valves; Hamra or Sundre Hamra or Sundre Fm., Gervalds, Vamlingbo; N NRM Br109714. Fm., Gervalds, Vamlingbo; C, M NRM Br34671. Posterior and Ventral interior; Hemse group, Petesvik, Hablingbo; O NRM ventral views of conjoined valves; Ho¨gklint Fm., Visby; H NRM Br32937; posterior view of conjoined valves; Hemse group, Petesvik, Br138227. Interior view of small dorsal valve with extremely thin Hablingbo; P NRM Br32938; posterior view of conjoined valves; shell; Hemse group, Lau kanal, Lau; I, I* NRM Br32921; posterior Hemse group, Petesvik, Hablingbo view and detail of conjoined valves; Hemse group, Petesvik,

1871 Strophomena filosa (J. de C. Sowerby).— 1974 Leptostrophia filosa (J. de C. Sowerby).—Calef Davidson: 307, pl. 45, Figs. 14–20 & Hancock: pl. 106, Fig. 12 1884 Strophomena filosa (J. de C. Sowerby).—La 1974 Leptostrophia filosa (J. de C. Sowerby).— Touche: 70, pl. 13, Figs. 406, 407 Bassett & Cocks: 15 1893 Leptostrophia filosa (J. de C. Sowerby).—Hall & 1977 Leptostrophia (Leptostrophia) filosa (J. de C. Clarke: 288 [name only] Sowerby).—Bassett: 145, pl. 39, Figs. 3–8 1921 Leptostrophia filosa (J. de C. Sowerby).—Hede: 1978a Leptostrophia (Leptostrophiella) filosa (J. de C. 92 [name only] Sowerby).—Harper & Boucot: 75 [name only] 1951 Leptostrophia filosa (J. de C. Sowerby).— ?1978a Leptostrophia (Leptostrophiella) sp.—Harper & Williams: 125 [name only] Boucot: pl. 5, Figs. 4a, b, 6, 8a, b 1963 Leptostrophia filosa (J. de C. Sowerby).— Holland et al.: pl. 3, Figs. 3, 5 Lectotype: GSM Geological Society Collection 6644, 1971 Leptostrophia (Leptostrophia) filosa (J. de C. external mold of dorsal valve; from the Wenlock Coal- Sowerby).—Bassett: 315, pl. 56, Figs. 9, 10; pl. bookdale Formation of Old Castle, Malvern Hills, UK; 57, Figs. 1–6 selected and figured by Bassett 1971, p. 317, pl. 57, Fig. 5;

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 217 originally figured J. de C. Sowerby in Murchison 1839, pl. presence (in Protomegastrophia) or absence (in Brachyp- 13, Fig. 12. rion) of the alveolus (the cardinal process pit of Williams et al. 1997, p. 424). In the Anticosti material of B. leda Remarks: Harper and Boucot (1978a) assigned M. (M.) described by Dewing (1999), this character is present in filosa to their new subgenus Leptostrophia (Leptostrophi- some specimens and absent in others. He therefore treated ella). This subgenus was regarded by Rong and Cocks the two (sub)genera as being synonymous. Cocks and Rong (1994) as a subjective synonym of Mesoleptostrophia, and (2000)separatedEomegastrophia, Brachyprion and Proto- I agree with them that the species does not belong to megastrophia on the basis of degree of concavoconvexity Leptostrophia since there are no radial ridges within the and the strength of the ventral muscle-bounding ridges. The ventral muscle field. There is also a ventral process rather ornament varies equally in all three genera. The youngest than a tubular chamber, and the ornament has no hint of genus (Protomegastrophia) has stronger convexity and rugae. more strongly impressed muscle fields than the two earlier The description of this species by Bassett (1977, p. 145) taxa, but both these traits are typical of large-sized speci- is generally applicable also for the Gotland specimens, with mens. Here I follow the opinion of Dewing (1999); he the following amendments. Many of the Gotland speci- considered Protomegastrophia to be a junior synonym of mens are almost as long as wide; ornament is usually fine, Brachyprion (Brachyprion), lacking dental plates, while equally parvicostellate, but can be unequally parvicostellate the presence of these plates in Eomegastrophia made him (Fig. 8C) or coarsely costellate (Fig. 8J, L); the former include that taxon as a subgenus of Brachyprion. I consider pattern is seen in low-energy the latter in high-energy Brachyprion to also contain B. (Erinostrophia) (see below environments; almost the entire hinge line is denticulate. for an emended diagnosis and discussion of this subgenus). Distribution: On Gotland M. (M.) filosa is the most Brachyprion (Brachyprion) semiglobosa (Davidson, widespread strophomenide, both geographically and tem- 1871) (Fig. 9) porally. It occurs throughout the succession from the Visby Formation to the Hamra Formation, in all environments. v.1847 Leptaena imbrex (Pander).—Davidson: Although widespread, it seems to be especially common 55, pl. 12, Figs. 25–28;—non Pander 1830 in relatively high energy settings; it is one of the few v.1848 Leptaena imbrex (Pander).—Davidson: strophomenides found in the shallow water, very high- 318, pl. 3, Fig. 8;—non Pander 1830 energy stromatoporoid-dominated environments of the v.1854 Strophomena imbrex (Pander).—Salter in eastern part of the Klinteberg Formation and Hemse group Murchison: table on p. 488, woodcut 41, (the others being Leptaena depressa depressa, Lepidol- p. 224, Figs. 6, 7;—non Pander 1830 eptaena poulseni and Shaleria (Janiomya) ornatella). It is v*1871(part) Strophomena imbrex (Pander) var. also fairly common in the Wenlock of the Welsh Borderland semiglobosa Davidson.—Davidson: 286, and South Wales, but rare or absent after mid-Ludlow times. pl. 41, Figs. 1–4, non Figs. 5, 6 v.1883 Strophomena imbrex var. semiglobosa Genus Brachyprion Shaler, 1865 Davidson.—Davidson: 195 Subgenus Brachyprion (Brachyprion) Shaler, 1865 v.1953 Megastrophia semiglobosa (Davidson).— Williams: 21 Type species: By original designation; Strophomena v.1971(part) Megastrophia (Protomegastrophia) semi- leda Billings, 1860, p. 55, Figs. 2, 3; Jupiter Formation, globosa (Davidson).—Bassett: 308, pl. 54, Anticosti Island. Figs. 9–13, pl. 55, Figs. 1, 2; non pl. 55, Remarks: In the Silurian, small and moderately conc- Fig. 3 avo-convex leptostrophiids have generally been referred to v.1974 Megastrophia (Protomegastrophia) semi- Brachyprion, while larger and more deeply concavo-convex globosa (Davidson).—Bassett & Cocks: ones have been referred to Protomegastrophia Caster, 17 1939. However, the redescription of the type species of v.1974(part) Brachyprion spp.—Bassett & Cocks: 15 Brachyprion, B. leda (Billings, 1860) by Dewing (1999) [partim] shows that even if that species is usually relatively small, v.1977 Megastrophia (Protomegastrophia) semi- there is great variation in convexity. The range of variation globosa (Davidson).—Bassett: 141, pl. 37, in convexity of B. leda is very similar to that seen in the Figs. 1–5 material of B. (B.) semiglobosa from Gotland. Harper ?1978c(non?) Brachyprion (Protomegastrophia) cf. semi- and Boucot (1978c) separated Brachyprion and Proto- globosa (Davidson).—Harper & Boucot: megastrophia (as subgenera of Brachyprion) only by the 18, pl. 38, Fig. 4, 6–8, non? Figs. 3, 5

123 218 O. A. Hoel

Fig. 9 Brachyprion semiglobosa (Davidson, 1871). Scale bar 1 cm, Va¨skinde; I–K, J* NRM Br33874. Lateral, ventral and dorsal views except in figures F*, F**, P*, S* = 0.5 cm, and Fig. J* = 0.3 cm. A, of conjoined valves. J*; detail of ventral valve sculpture; Slite group, B NRM Br118262. dorsal and posterior views of conjoined valves; Stora Karlso¨; L NRM Br119571. Ventral valve interior, view Slite group, Va¨stergarn, Va¨stergarn; C–E NRM Br34685. Ventral, perpendicular to the interarea; Ho¨gklint Fm., Visby; N, O NRM posterior and dorsal views of conjoined valves; ?Ho¨gklint Fm., Br123373. Ventral and lateral views of semicircular, strongly vaulted Va¨skinde; F, F*, F** NRM Br 131189. Ventral valve interior; views: dorsal valve; Slite group, Ba¨cks, Akeba¨ck; P, Q, P* NRM Br35914. F, F** perpendicular to the commisure; F* parallel with the interarea; Ventral and posterior views of semicircular, strongly vaulted dorsal Upper Visby Fm., Gnisva¨rd, Tofta; G, H, M NRM Br34689. Ventral, valve; Slite group, Atlingbo church; R–S, S* NRM Br35895. Lateral dorsal and posterior views of conjoined valves; ?Ho¨gklint Fm., and ventral views of wide, flat dorsal valve; Visby Fm., Visby

v.1978c Brachyprion (Protomegastrophia) sp.— Distribution: B. (Brachyprion) semiglobosa is common in Harper & Boucot: pl. 37, Figs. 1–11, pl. all environments within the lower part of the Gotland suc- 38, Fig. 9 cession, from the Visby Formation through the whole of the v.2004 Brachyprion sp.—Musteikis & Cocks: 464 Slite group. A few specimens have also been found in the Klinteberg Formation at Klinteberg. There is no evidence to Remarks: The species was described by Bassett (1977), suggest that it is present further east in the Baltic (Musteikis and there is little to add to his description. As noted by and Cocks 2004). In the British Isles it occurs in the upper Bassett (1977, p. 142), the Gotland material displays wide Llandovery of the Malvern area (Harper and Boucot 1978c, variability in profile; most are more elongate and less pl. 38, Figs. 4, 6–8), and it is relatively rare in the upper deeply convex than the British specimens. Some Gotland Wenlock of the Welsh Borderlands and south-central Wales specimens also have the more widely spaced primary (Bassett 1977, p. 140). Possibly the specimens from the costellae seen in P. quetra Bassett (1977, p. 142), but are upper Wenlock of the Llandovery area figured by Harper and not as large and thick-shelled as that species. Boucot (1978c, pl. 38, Figs. 3, 5) also belong to this species.

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 219

Subgenus Brachyprion (Erinostrophia) Cocks & v.1978 Megastrophia (Protomegastrophia) undata Worsley, 1993 (M’Coy).—Cocks: 128 v.1993(part?) Erinostrophia undata (M’Coy).—Cocks & Type species: By original designation; Orthis undata Worsley: 44-45, Fig. 8b–f, ?non Fig. 8a M’Coy, 1846;p.36.

Emended diagnosis: Strongly concavo-convex; pro- Type specimens nounced but discontinuous rugae over whole shell in most specimens. Cardinal process lobes rounded, undercut Lectotype of walmstedti (selected by Bassett & Cocks laterally; dorsal muscle bounding ridges absent; dorsal 1974, p. 16): NRM Br102367, conjoined valves; original adductor scars narrow, centrally placed; transmuscle ridges of Lindstro¨m 1861, pl. 13, Fig. 16, from the lower Visby long and strong, almost parallel to the midline, diverging Formation (Telychian), Visby, Gotland, Sweden. Refig- less than 158 from the mid line of the valve. ured by Bassett and Cocks 1974, pl. 3, Fig. 5a–d. Remarks: The subgenus was erected (as a genus) Lectotype of undata (selected by Cocks 1978, p. 128): entirely on the basis of its distinctive ornament of irregular NMING: F7475, an internal mould of a dorsal valve; rugae, but this feature is very subdued on many of the original of M’Coy 1846, pl. 3, Fig. 21 from Kilbride Gotland specimens of E. walmstedti, and firmer grounds for Sandstone (Telychian), Egool, Ballaghadareen, County separation should be established to warrant recognition. Mayo, Ireland. Refigured by Cocks and Worsley 1993, Cocks and Worsley (1993, p. 44) noted that the cardinal Fig. 8A. process lobes of Erinostrophia and Protomegastrophia are erect, whereas those of Brachyprion leda are anterior-facing. Diagnosis: Cardinal process lobes strong, divergent, As discussed above, Protomegastrophia is considered a strong socket ridges, and long, subparallel dorsal trans- junior synonym of Brachyprion, and the cardinal process muscle ridges. lobes of B.(Brachyprion) semiglobosa are indeed erect like Description: The species was described adequately by those of E. walmstedti. Bassett and Cocks (1974, p. 16), but as some of the material B.(Erinostrophia) differs from B. (Brachyprion)in they studied apparently was badly preserved, some additions having rugae, in the shape of the notothyrial platform, to their description of the ventral interior can be made: which lack muscle bounding ridges completely, in the Ventral muscle field deeply recessed, but without muscle laterally undercut cardinal process lobes, in having cen- bounding ridges, except anterior to the diductor scars, where trally placed dorsal adductor scars and in having almost there is a very low rim. Muscle field divided longitudinally parallel transmuscle ridges. B.(Erinostrophia) differs from by a thin, low median ridge, which swells somewhat anterior B. (Eomegastrophia) in lacking dental plates and in having to the adductor scars and dies out at the anterior margin of a more deeply impressed ventral muscle field, which usu- the diductor scars. Delthyrial cavity filled by the large ally has an unbounded anterior margin. ventral process, which extends forwards and is forked rather far posteriorly. On both sides of the ventral process there are Brachyprion (Erinostrophia) walmstedti (Lindstro¨m, deep pits accommodating the cardinal process lobes; ante- 1861) (Fig. 10) rior to these there is a smooth surface lateral to the adductor scars and posterior to the recessed diductor scars. Posterior ?1846 Orthis undata—M’Coy: 36, pl. 3, Fig. 21 adductor scars large, triangular; anterior adductor scars v*1861 Strophomena walmstedti—Lindstro¨m: small, rounded. Diductor scars large, recessed and kidney- 372, pl. 13, Fig. 16 shaped, with unbounded anterior margin. There is no trace v.1868 Strophomena walmstedti Lindstro¨m.— of the muscle scars being flabellate as believed by Bassett Davidson: 18, pl. 3, Figs. 5–7 and Cocks (1974). The extra-muscular area has coarse v.1871 Strophomena walmstedti Lindstro¨m.— taleolae lateral to the muscle field, but anteriorly the surface Davidson: 290, pl. 40, Figs. 6–8 is covered by very densely packed, minute taleolae. The v.1916 Brachyprion walmstedti (Lindstro¨m).— vascula media bifurcate several times anteriorly, forming a Holtedahl: 39-40, pl. 5, Figs. 6–8 large number of relatively wide mantle canals at the com- v.1974 Megastrophia (Protomegastrophia) wal- misure, but only along the anterior half of the commisure; mstedti (Lindstro¨m).—Bassett & Cocks: posteriorly there are no vascular traces. 16, pl. 3, Figs. 5–9 v.1978 Brachyprion (Brachyprion) walmstedti Remarks: Cocks (1978) placed B.(E.) walmstedti into (Lindstro¨m).—Harper & Boucot: 16 synonymy with B.(E.) undata (M’Coy, 1846), solely on

123 220 O. A. Hoel

123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 221 b Fig. 10 Brachyprion (Erinostrophia) walmstedti (Lindstro¨m, 1861). Holotype: NRM Br 102617a, a dorsal valve interior, Scale bar 1 cm, except in figures D*, H*; I*, M* = 0.5 cm, from the Hamra Formation at Hoburgen, Sundre parish, C* = 0.2 cm. A–C, C* PMU EP203. Conjoined valves. Ventral, posteroventral, interareal views and detail of delthyrial area to show Gotland, figured in Fig. 11I, I*. pattern of growth by mantle retractions; D, G, D* NRM Br33988. Diagnosis: Profile moderately concavoconvex, strong, Ventral interior. Views parallel to the interarea and normal to the commisure, with detail of the muscle field. Note how the diductor uniformly costellate sculpture, denticles along about half scars are sharply delimited posteriorly; E, F PMU EP201. Conjoined the hinge line, raised adductor scars in the ventral valve; valves. Views from the postero-lateral side and normal to the dorsal muscle scars faint, transmuscle ridges wide and commisure; H–J, H*–I* SGU 9221. Dorsal valve. Interior, posterior, strong distally. lateral views, and detail of the cardinal area. Note the kidney-shaped adductor scars and the round ‘‘secondary socket ridge’’; K–M, M* Description: Shell outline usually semicircular, widest at SGU 9222. Ventral valve. Views normal to the commisure, normal to the interarea and parallel to the interarea, with detail of muscle field. the posterolateral margins; the latter are often extended into Note the small anterior adductor scars long, rather thin alae. Profile moderately concavoconvex without any geniculation; ventral beak prominent, in some specimens with a small apical foramen, overhanging the the basis of the presence of rugae on both forms. B.(E.) hinge line. Ventral interarea short, weakly apsacline at the undata is not well known; only the single badly preserved umbo, but catacline towards the hinge line; traces of the lectotype has ever been found, and it does not show much growth path of denticles is visible. Delthyrium very narrow detail apart from the sculpture, but judging from the photo- near the apex where it is covered by a small pseudo- graph in Cocks and Worsley (1993, Fig. 8a), the cardinal deltidium, and subsequently widens sharply towards the process seems to be relatively much smaller than in the hinge line. Dorsal interarea shorter than the ventral area, Gotland specimens and also smaller than in the Norwegian anacline, nothothyrium small, filled by the cardinal process specimens figured by the same authors (Fig. 8e, f). Davidson and covered by a small chilidium. Ornament of coarse, (1879, p. 290, pl. 40) assigned specimens from the Pentland subequal, slightly irregular parvicostellate, about 2 per mm. Hills to walmstedti rather than undata, despite having seen Delthyrial cavity filled by strong ventral process, which M’Coy’s material. I therefore retain the species name is slightly concave centrally, process pits shallow but walmstedti until study of better material of the Irish species almost as large as the adductor scars. No trace of teeth, can confirm the synonymy or otherwise of the two forms. denticles along about half shell width. Muscle field occu- Distribution: On Gotland, B.(E.) walmstedti occurs pies 50% of shell length and 33% of valve width, trian- quite commonly in both the lower (Telychian) and upper gular, slightly depressed but without bounding ridges. (Sheinwoodian) parts of the Visby Formation along the Adductor scars large, bean-shaped, raised above the valve northwest coast from Lummelunda in the north to Tofta in floor and separated by a median ridge, which is concave the south. In the Oslo Region (Norway), it is common in centrally; this ridge dies out at the anterior end of the the upper part of the Bruflat and Porsgrunn formations adductor scars, but anterior to this there is a slight swelling (latest Telychian) and in the Braksøya Formation (Shein- which bifurcates into two low, wide ridges, which encircle woodian) (Worsley et al. 1983, Cocks and Worsley 1993), a shallow depression at about 50% of valve length. Di- and it also occurs in the Telychian of the Pentland Hills, ductor scars long and wide, anterior end of muscle scars Borders Region, UK (Davidson 1871, p. 290). Most of indistinct, but on weathered specimens a discoloration these occurrences appear to be in relatively shallow, but shows the anterior end to be rounded. The extra-vascular low-energy depositional environments. area is covered with large pseudopunctae, which are larger and more pronounced lateral to the muscle field and around Family Strophodontidae Caster, 1939 the anterocentral depression. Genus Strophodonta Hall, 1850 In the dorsal valve, there is neither a bounding ridge nor a Subgenus Strophodonta (Strophodonta) Hall, 1850 clear geniculation, but a slight increase of curvature outside the muscular area is visible in some specimens; hinge line Type species: By original designation; Strophomena denticulate along more than 50% of its length, usually about demissa Conrad, 1842, p. 258, pl. 14, Fig. 14; from the 75%. Socket ridges very short, subparallel with hinge line. Emsian-Givetian of New York and the Eifelian-Frasnian of Cardinalia strong, raised on a notothyrial platform, which is Maryland, USA. elevated and curves around the posterior of the adductor Strophodonta (Strophodonta) hoburgensis n. sp. scars in young specimens, but is recessed in gerontic ones. (Fig. 11) Cardinal process lobes massive, rising vertically from the notothyrial platform, joined proximally, slightly diverging, Derivation of name: From the type area of the species. with attachment faces pointing posteriorly. Adductor scars

123 222 O. A. Hoel

Fig. 11 Strophodonta (Strophodonta) hoburgensis n. sp. Scale bar scars and strong ventral process; Sundre Fm., Juves, Sundre; D, D* 1 cm, except in figures B*, D*, G*, I* = 0.5 cm, A* = 0.33 cm. NRM Br102617f. small dorsal interior; E–G, G* NRM Br34144. Specimens A, D, H, I are from a single bedding plane in the Hamra Three views of slightly crushed ventral valve. Note elevated adductor Fm., Hoburgen, Sundre; A, A* NRM Br102617b. Ventral exterior; B, scars; Hamra Fm., Valkmyrs kanal, Vamlingbo; H NRM Br102617c. B* NRM Br34086. Dorsal view of conjoined valves with very long Ventral exterior; I, I* NRM Br102617a. Dorsal interior with strong alae. Note pseudodeltidium and small foramen; Hamra Fm., Vam- transmuscle ridges; J NRM Br138253. Ventral valve with long alae; lingbo; C NRM Br123622. Ventral interior. Note elevated adductor Sundre Fm., Hallbja¨ns, Sundre slightly impressed in young specimens, almost invisible in almost effaced dorsal muscle field, no radial ridges in the gerontic ones, divided by a strong medial ridge, which ventral diductor scars, and in having both pseudodeltidium reaches almost to the anterior margin, and subdivided by and chilidium protruding from the interareas. This is the trans-muscle ridges, which in gerontic specimens widen earliest known member of the genus (noted to range from distally into arrowhead shaped platforms. The entire inner the Prˇidolian to the Frasnian in Cocks and Rong 2000). surface is covered in relatively large, widely spaced Harper and Boucot (1978c, p. 36) noted the presence of a pseudopunctae arranged in radial rows near the outer shell species of Strophodonta on Gotland, but their locality margin, but randomly within the muscular area. The inner reference (CHG28) is untraceable, as it is not defined in surface is not strongly influenced by the exterior ornament. their paper and is also unlike all other locality references in that publication. They cited the age to be Prˇidolian (the Remarks: S. (S.) hoburgensis n. sp. differs from the type youngest beds on Gotland are late but not latest Ludlow), species S. (S.) demissa in having denticles along a smaller which suggests that their material must be from the latest part of the hinge line, more parallel cardinal process lobes, 123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 223 part of the succession, and thus probably conspecific with developed unequal parvicostellate or costellate sculpture the present species. without rugae. The two dorsal interiors in the present material (Fig. 12G, Distribution: From the collections of NRM and SGU, G*, J) show no dorsal side septa and are rugate, but one of Strophodonta (Strophodonta) hoburgensis n. sp. seems to them is associated with other apparently non-rugate valves be present only in the Hamra and Sundre Formations. showing diductor scars similar to those in Shaleria ornatella Family Shaleriidae Williams, 1965 (see also Harper and Boucot 1978b, pl. 35, Figs. 1–10). Genus Shaleria Caster, 1939 Subgenus Shaleria (Janiomya) Havlı´cˇek, 1967 Type species: By original designation; Strophomena (=S. (Protoshaleria) Harper & Boucot, 1978) gilpeni Dawson, 1880, p. 341; from the Ludlow-early Devonian of Nova Scotia, Canada. Type species: By original designation: Janiomya paral- lelomya Havlı´cˇek, 1967, p. 175–176, pl. 36, Figs. 3–5; Remarks: All specimens from Gotland identified within from the Budnˇanian (Ludlow- Prˇ´ıdolı´) of Bohemia, Czech the genus Shaleria are morphologically very similar and Republic. originate from a restricted area from beds deposited in only a few million years. Yet they exhibit subtle variations in Remarks: S (Protoshaleria) was synonomized with sculpture and diductor scar shape. Similar variations have Shaleria (Shaleria) by Cocks and Rong (2000), but the been used previously as defining characters for genera and undivided shape of the ventral diductor scars and the single subgenera within the group (e.g., Harper and Boucot 1978b, pair of small dorsal side septa make the species referred to p. 160): The difference between Shaleria Caster, 1939 and this subgenus by Harper and Boucot (1978b, p. 163) more Shaleriella Harper & Boucot, 1978 is defined as the latter similar to the type species of S. (Janiomya) than to being slightly geniculate, having zig-zag rugae and lacking S. gilpeni, which has a strong second pair of diductor scars dorsal side septa (see Cocks and Rong 2000). Harper and and two pairs of long dorsal side septa. Boucot (1978b) referred species with dorsal side septa but Shaleria (Janiomya) ornatella (Davidson, 1871) with rugae to Shaleria (Protoshaleria) (not recognized by (Fig. 12A–L) Cocks and Rong 2000), while species without rugae and lacking side septa were referred to Shaleria (Janiomya) v*1871 Strophomena ornatella—Davidson: 309, pl. 43, Havlı´cˇek, 1967, and those with two pairs of side septa to S. Figs. 16–20 (Shaleria). Several of the specimens of Shaleriella delicata v.1902 Strophomena impressa Lindstro¨m.—Munthe: figured by Harper and Boucot (1978b, pl. 34, e.g., Figs. 15, 233-234, Figs. 3–4 20, 23) do not have rugate sculpture, and all the specimens v.1921 Leptostrophia impressa (Lindstro¨m).—Hede: 92 are also small, which casts doubt upon the lack of dorsal [name only] side septa being a valid character. That leaves the genicu- v.1925 Leptostrophia impressa (Lindstro¨m).—Hede: 48 lation as the single defining character, but Shaleria [name only] (Shaleria) honeymani McClearn, 1924 is also geniculate v.1939 Shaleria ornatella (Davidson).—Caster: 34 while having subequally costellate sculpture (Harper 1973, v.1963 Shaleria ornatella (Davidson).—Holland et al.: pl. 13, Figs. 8, 10). This shows that the differences between 154, pl. 3, Fig. 1 Shaleria and Shaleriella are too small for generic differ- v.1974 Shaleria aff. ornatella (Davidson).—Bassett & entiation, and Shaleriella is at most a subgenus of Shaleria. Cocks: 17 The inconsistency of the characters defining the subgenera v.1978 Shaleria ornatella (Davidson).—Cocks: 129 of Shaleria indicates that the genus perhaps should remain v.1978b Shaleria (Protoshaleria) ornatella undivided into subgenera, but this would also mask the (Davidson).—Harper & Boucot: 162, pl. 35, variability that after all is present and that seems to be Figs. 1–10 consistent within the species groups. ?1985 Shaleriella tenuis—Nikiforova, Modzalevskaya The Gotland specimens show most of this variation & Bassett: 23, pl. 5, Figs. 1–6 within the small samples available. The variation in v.1994 Shaleria (Janiomya) ornatella (Davidson).— sculpture appears to correlate with depositional environ- Rong & Cocks: 661, Fig. 11 ment; rugae are present in specimens from the relatively v.2004 Shaleria (Shaleria) ornatella (Davidson).— low-energy environments in the Hemse Marl at Visne Myr Musteikis & Cocks: 466, Fig. 5L–O, 6B–H and Hallsarve (both low in Hemse) and Lau kanal (top of the Hemse Marl), while those from the higher energy Lectotype: Selected by Cocks 1978; GSM 13397; a environment at Millklint (high in the Hemse Limestone) pedicle valve, the original of Davidson 1871, pl. 43, 123 224 O. A. Hoel

Fig. 12 A–N Shaleria (Janiomya) ornatella (Davidson, 1871). Scale Ventral interior; ?Eke Fm., Lau. Note the converging muscle bar 1 cm, except in figures G*, K* = 0.5 cm. A NRM Br138251. bounding ridges and the small size of the adductor scars; I, L NRM Ventral valve with strong rugae; Hemse group, Hallsarve, Lau; B, Br36125a. Natural mold and latex cast of ventral interior; Hemse C NRM Br134453a. Latex cast and natural mold of ventral exterior group, Millklint, Ardre; J NRM Br130704. Interior of dorsal valve. with strong, unequal costellae; Hemse group, Lau kanal, Lau; D NRM Hemse group; Visne Myr kanal, Ardre; K, K* NRM Br134452a. Br138248a. Two ventral interiors. Note the diverging muscle Exterior view and umbonal detail of rugate dorsal valve. Note shape bounding ridges; ?Eke Fm., Lau; E NRM Br36070a. Large ventral of dorsal umbo; Hemse group, Lau kanal, Lau; M–P Shaleria valve with very fine, equal costellae; Hemse group, Millklint, Ardre; (Shaleriella) ezerensis (Rybnikova, 1966); NRM Br119540, ventral F NRM Br36125d. Partly exfoliated ventral valve; Hemse group, valve interior in dorsal, lateral, posterior and posterolateral views; Millklint, Ardre; G, G* NRM Br138248c. Cardinal detail and interior Eke Formation, Petsarve 4, Eke. Note weak dorsal geniculation and views of small dorsal valve; ?Eke Fm., Lau; H NRM Br138247. relatively wide muscle field

Fig. 16 (top) from Upper Ludlow, Whitcliff, Ludlow, corners can be produced as short alae; profile gently con- Salop, UK. cavoconvex without geniculation. Ventral beak low but pronounced, slightly overhanging the interarea and bearing Description: Shell outline semicircular; length/width a small, sealed foramen at its apex; ventral interarea very ratio about 0.70–0.85; the widest part of the shell is usually narrow and apsacline to catacline; pseudodeltidium not slightly anterior to the hinge line, but the posterolateral well preserved in this material, delthyrium occupies about 123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 225

10% of the interarea width. Dorsal beak is a small, raised outline. They also have narrower interspaces between the knob situated slightly anterior to the hinge line; dorsal primary costellae and corresponding smaller number of interarea not seen in this material. Ornament usually smaller costellae within them. No rugae are found in the unequally parvicostellate with a variable number of smaller Millklint specimens, and one specimen is multicostellate costellae between the stronger, more elevated primary rather than unequally parvicostellate. In my opinion, these costellae, but some specimens are multicostellate with all differences are environmentally related, since the environ- costellae being very thin (Fig. 12E). In some specimens ment at Millklint apparently was a higher energy setting. (Fig. 12A), small rugae occur between the primary Musteikis and Cocks (2004) regarded the Podolian speci- costellae and are deflected by them into a slight zig-zag mens described as Shaleriella tenuis by Nikiforova et al. pattern. (1985) as belonging to Shaleria ornatella, but this is uncertain. The Podolian material differs from British and Delthyrial cavity shallow, most of it filled by a low Gotland specimens in having more denticles on the hinge ventral process, which supports the apical part of the line, a much more elongate outline and clearly geniculate pseudodeltidium. Proximal part of the medial process profile. It also differs from the British material figured by broad, but it narrows anteriorly into a thin ridge separating Musteikis and Cocks (2004, Fig. 5L–O) in having weaker, the diductor scars. The muscle area occupies about 30–50% unequally parvicostellate sculpture, but as discussed earlier, of shell length and about 20% of shell width. In most the sculpture of shaleriids seems to be strongly influenced specimens, the diductor scars are surrounded by more or by the environment and cannot be used for taxonomic less parallel muscle bounding ridges, and the anterior ends purposes. The ridges along the dorsal muscle field are much are distinct, but in some specimens the ridges diverge at more strongly developed in the Podolian (Nikiforova et al. about 25° to one another, and the anterior ends of the 1985, pl. 5, Figs. 5–6) and Latvian material (Musteikis and muscle scars are diffuse. The hinge line bears denticles on Cocks 2004, Fig. 6F–H) than in the few dorsal interiors of about 33% of its width; small teeth with crenulations are S. ornatella figured previously from the UK and Gotland present in some specimens, but most are damaged in (Davidson 1871, pl. 43, Fig. 18; Harper and Boucot 1978b, this area; teeth supported by dental plates, but these are pl. 35, Fig. 1b; Musteikis and Cocks 2004, Fig. 5M; and separate from the muscle bounding ridges. Adductor scars herein Fig. 12G, G*, J), although this may well be a func- very faint, only visible as shallow crescentic depressions tion of ontogenetic development. at the anterior margin of the broad ventral process. Extra-muscular area covered by relatively large and dis- Distribution: The specimens in the collections of NRM persed pseudopunctae; the interior is strongly impressed by are from the Hemse group in three different areas; one the exterior sculpture. group is from a low level within the Hemse group at Only two specimens from Gotland were sufficiently well Millklint, Ardre parish; another group is from a low level preserved to show details in the dorsal valve interior: The in the Hemse group at near Fardhem Church; the third cardinalia are relatively small but stout, and elevated on a group originate from probably just below the Hemse-Eke very low platform; cardinal process lobes united for 50% of boundary south of Lau church. Bassett and Cocks (1974) their height, with narrow attachment faces directed postero- recorded the species from the Hemse, Eke and Burgsvik ventrally, diverging at about 508 from one another. Socket beds, and specimens in the collections at SGU show a ridges strong, curving antero-laterally; hinge line bears range from the Hemse group and through to the Sundre denticles complementary to those of the ventral valve. Formation. The SGU collections show S. (J.) ornatella to Muscle scars indicated faintly by two pairs of short, low be especially widespread in the Burgsvik Formation. In the ridges originating from the anterior margin of the cardinal British Isles, it is known only from the Upper Ludlow rocks platform; these ridges bear larger pseudopunctae than the of the Ludlow District, Shropshire (Holland et al. 1963). rest of the valve surface; the interior is strongly impressed Remarks on ecology: Hede (1925, p. 37–45) recorded by the exterior sculpture this species (as L. impressa) at Lau kanal, Hallsarve, and Remarks: The specimens with divergent muscle Lau Backar, where he notes that it occurs from the upper bounding ridges and diffuse anterior muscle scar margins Hemse group and into the Eke Formation, and that it is could be mistaken for specimens of Leptostrophia, but in extremely abundant in a thin layer at the top of the Hemse that genus the entire hinge line is denticulate and there are group. From his profile descriptions, the species appears to no teeth. The specimens referred previously to Shaleria be most common in relatively shallow water, sandy envi- impressa (see Munthe 1902, Figs. 3, 4) are here referred to ronments; in the same area, the top of the Hemse group is S. ornatella. The specimens from Millklint (Hemse Lime- marked by submarine hardground horizons and quite deep stone) are somewhat different from the specimens from erosion, while the overlying Eke Formation represents Lau kanal (Hemse Marl) in having a more transverse high-energy environments within normal wave base 123 226 O. A. Hoel

(Cherns 1982, 1983). Calef and Hancock (1974) record process, which supports the apical part of the pseudo- Shaleria as a moderately common constituent of the Lud- deltidium; this medial process is raised on a platform low Isorthis community, and in Wales it is confined to that posteriorly; anterior margin of the platform excavated to community. According to these authors, this community form two small depressions flanking the anterior projection corresponds approximately to the Llandovery Stricklandia of the ventral process. The hinge line bears denticles only a community of Ziegler et al. (1968) and is typical of rela- short distance laterally from the delthyrium; no dental tively offshore environments. Harper and Boucot (1978c, plates present. Muscle field elongate, diductor scars sub- p. 10) on the other hand, state that shaleriids are typical of parallel with rounded anterior margins; lateral bounding Benthic Assemblage 2, which has been interpreted as ridges high posteriorly, very low but visible anteriorly; subtidal (Boucot 1975). The Gotland shaleriid material adductor scars short and narrow, posteriorly placed; extra- supports the latter interpretation in that they occur in muscular area covered in large, radially arranged taleolae; apparently shallow water sediments, especially at Lau no vascular traces visible. backar, where other brachiopods [e.g., Lepidoleptaena Remarks: Only a single specimen with the geniculate poulseni (Kelly, 1967)] are often coated with oncolithic profile supposedly characteristic for this species was found crusts deposited by algae (see Hoel 2005, Fig. 8). in the collections of NRM. It is from Petsarve 4, which is in Subgenus Shaleria (Shaleriella) Harper & Boucot, a high level within the Eke Formation, while all other 1978 shaleriid specimens in the collections of NRM originate from the uppermost Hemse group or lower Eke Formation Type species: By original designation: Shaleriella deli- and are not geniculate. A specimen found by me in a cata n. sp. Harper & Boucot 1978b, p. 160–161, pl. 34, sandstone from the upper part of the Burgsvik Formation is Figs. 11–25, 29, from the late Ludlow Hemse group and Eke identical to the NRM specimen, other than lacking geni- Formation of Gotland [subjective synonym of Shaleria culation. Strangely enough the specimens figured by (Shaleriella) ezerensis (Rybnikova, 1966) from the Prˇ´ıdolı´an Musteikis and Cocks (2004, Figs. 5P, 6A) as S. ezerensis Ju¯ra Formation of Latvia, see Musteikis and Cocks, p. 468]. from the Hemse group at Millklint are apparently not geniculate. They are similar to the specimens figured as Remarks: As discussed above, the diagnostic features of S. ornatella herein from Millklint (Fig. 12E, I, L). The Shaleriella are not sufficiently specific to warrant generic holotype of S. ezerensis, as well as the other Latvian status, but the variation is considered too wide to allow specimens figured by Musteikis and Cocks (2004), have Shaleria to remain undivided into subgenera. much stronger geniculation than the Gotland specimens Shaleria (Shaleriella) ezerensis (Rybnikova, 1966) figured as S. delicata by Harper and Boucot 1978b, to the (Fig. 12M–P) point that they display a fold-and-sulcus, of which there is no trace in the Gotland specimens. v*1966 Brachyprion ezerensis—Rybnikova: 80, pl. 1, Distribution: Harper and Boucot (1978b, p. 161) recor- Figs. 9, 10 ded this species (as S. delicata) from the upper part of the v.1967 Brachyprion ezerensis Rybnikova.—Rybnikova: Slite group very close to the Bara Oolite, the middle part of 193, pl. 21, Figs. 1, 2 the Hemse Group near Linde klint, upper part of the Hemse v.1978 Shaleriella delicata n. sp.—Harper & Boucot: group and lower Eke Formation near and on the Eke out- 161, pl. 34, Figs. 11–25, 29 liers of Lau backar and Burgen in the east, and near Eke v.2000 Shaleriella delicata Harper & Boucot.—Cocks church in the west, and high in the Eke marl at Ronehamn. & Rong: 302, Fig. 192: 2a-c The latter locality is very near the locality and stratigraphic v.2004 Shaleria (Shaleriella) ezerensis (Rybnikova).— level of the specimen figured herein. I have also found Musteikis & Cocks: 468, Figs. 5P, 6A, I–P specimens of this species near the boundary between the Burgsvik and Hamra formations at Ka¨ttelviken. All these Holotype: LMNH Br.30/12, a ventral exterior from the localities were in high-energy environments. Prˇidoli Ju¯ra Formation, at the 926.8-m level in the Ezere borehole, Latvia. Refigured by Musteikis and Cocks (2004, Ecological remarks Fig. 6I) (Holotype of S. delicata: By original designation: USNM 220911; a, from Hemse marl (at Gogs, Lau parish, The study of leptaenines on Gotland (see Hoel 2005, 2008) Gotland), figured by Harper and Boucot 1978b, pl. 34, revealed a morphological trend linked to the depositional Fig. 17.) environment, especially the water energy: Specimens Description of the specimen (NRM Br119540): found in low-energy environments have subdued concentric Delthyrial cavity shallow, mostly filled by a low ventral ornament and closed apical foramina, whereas those from 123 Strophomenidae, Leptostrophiidae, Strophodontidae and Shaleriidae (Brachiopoda, Strophomenida) 227 higher energy environments have strong concentric orna- which is confined to the low-energy Mulde marl of the ment and open apical foramina. In all three genera studied Halla Formation. herein there are comparable morphological trends: In the The other ‘‘strophodontids’’ on Gotland have long Visby beds, the specimens of Pentlandina tartana have ranges and wide environmental tolerances; Mesolepto- regular shape, weak ornament and usually a small, open strophia filosa and Brachyprion (Brachyprion) semiglob- pedicle foramen (Fig. 4); in the Ho¨gklint beds, specimens osa occur in both high- and low-energy environments of P. loveni are irregular, with stronger concentric orna- without any marked morphological variation, neither due to ment, and large pedicle foramen. In the Slite beds, the environment or micro-evolution. M. filosa was also rec- specimens of P. lewisii (Fig. 5W–Af) have no pedicle ognized as having a very wide environmental tolerance by foramen and mostly only radial ornament (as in Leptaena Calef and Hancock (1974), who noted that the species depressa, see Hoel 2005). The single specimen of occur in every brachiopod community recognized in the P. cf. lewisii (Fig. 5U, V) from the Klinteberg Formation Wenlock and Ludlow of Britain, from inshore to deep presumably is phylogenetically closer to P. lewisii, but is water. Apparently the moderately concavo-convex shell morphologically quite similar to P. loveni in having a profile and subdued shell ornament were a very successful strong concentric ornament and large pedicle foramen. A adaptation evolved many times in many different lineages. similar influence on shape and ornament is seen in Kata- Similar morphology and distribution are also found in strophomena, where the low-energy environments of the Strophonella euglypha, Amphistrophiella funiculata and Visby Formation contains K. penkillensis with triangular the chilidiopside Coolinia. shell outline, thin shells and ornament of thin, widely spaced costellae and very fine rugae (Fig. 6A, G), whereas Acknowledgments This work was carried out at the Department of the slightly higher energy environments of the Hemse Geosciences, Palaeobiology Program, Uppsala University, as part of my Ph.D. project. I am grateful to Professor Michael Bassett, Cardiff, group contain K. antiquata scabrosa with semi-circular for initiating the project on Gotland Strophomenides and for many outline, thick shells and strong, closely spaced, gnarly helpful comments on the manuscript, and to Professor Lars Holmer, costellae (e.g., Fig. 7A, E). Similar strong ornament is also Uppsala, for help throughout this work. Photographic assistance and seen in specimens of K. penkillensis in the high energy comments were provided by Dr. Jan Ove Ebbestad and Dr. Christian Skovsted, Uppsala. Christina Franze´n Bengtsson (NRM) and Lars environment of the Ho¨gklint Formation (Fig. 6J). In Karis (Swedish Geological Survey, Uppsala) kindly made the large Bellimurina wisgoriensis the environmental influence on collections of their institutions available for study. morphology is seen within a single species between spec- imens from the Visby Formation (with subtly expressed Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- costellae and rugae, and geniculation) and from reefs of the mits any noncommercial use, distribution, and reproduction in any Ho¨gklint Formation (with strong ornament, frilly growth medium, provided the original author(s) and source are credited. lamellae and a much stronger development of the ante- rior fold-and-sulcus). In higher energy environments Bellimurina wisgoriensis and Pentlandina loveni both References develop strong, diamond-shaped shell ornament by the interplay of costellae and rugae and a more pronounced Baarli, B.G. 1995. Orthacean and strophomenid brachiopods from the irregularity of overall shell shape than their low-energy Lower Silurian of the central Oslo Region. Fossils and Strata 39: environment counterparts. The morphological response to 1–93. Bancroft, B.B. 1949. Welsh Valentian brachiopods and the Strop- environmental changes is thus quite similar in all three homena antiquata group of fossil brachiopods, ed. A. Lamont, genera. Privately printed. 16 pp., 3 pls. Mexborough. In contrast to the morphological plasticity in response to Bassett, M.G. 1971. Wenlock Stropheodontidae (Silurian Brachio- environmental factors seen in the Leptaenines and furci- poda) from the Welsh Borderland and south Wales. Palaeontol- ogy 14: 303–337. tellinines, all of the ‘‘strophodontids’’ described in the Bassett, M.G. 1974. The articulate Brachiopods from the Wenlock present paper display only minute variability, and this Series of the Welsh Borderland and South Wales. Monographs cannot be related to differences in environment. Three of of the Palaeontographical Society. Part 3 (pp. 79–122, pls. the species [the strophodontide Strophodonta hoburgensis 18–32). Bassett, M.G. 1977. The articulate Brachiopods from the Wenlock n. sp. and the shaleriids Shaleria (Janiomya) ornatella and Series of the Welsh Borderland and South Wales. Monographs S. (Shaleriella) ezerensis] have short ranges and occur only of the Palaeontographical Society. Part 4 (pp. 123–176, in high-energy environments, while the leptostrophiide pl. 33–47). Brachyprion (Erinostrophia) walmstedti is likewise short Bassett, M.G. 1985. Silurian stratigraphy and facies development in Scandinavia. In The Caledonide Orogen Scandinavia and related ranged, occurring only in the low-energy Visby Formation. areas, ed. D.G. Gee, and B.A. Sturt, 283–292. London: Wiley. Another ‘‘strophodontide’’ with similar narrow temporal Bassett, M.G.B. and Rong J.-Y. 2002. Brachiopods. In: Telychian and ecological ranges are Mesopholidostrophia laevigata, rocks of the British Isles and China (Silurian, Llandovery 123 228 O. A. Hoel

Series), eds. Holland, C.H. and Bassett, M.G.B., National Hall, J. 1850. On the Brachiopoda of the Silurian Period. Proceedings Museums and Galleries of Wales, Geological Series 21: of the American Association for the Advancement of Science 2: 124–136. 247–351. Bassett, M.G.B. and Cocks, L.R.M. 1974. A review of Silurian Hall, J. and Clarke, J.M. 1892–1895. An introduction to the study of brachiopods from Gotland. Fossils and Strata 3: 1–56, pl. 1–11. the genera of Paleozoic Brachiopoda. New York Geological Billings, E. 1860. Description of some new fossils from the lower and Survey, Paleontology of New York 8:1: 1–367, pls. 1–20 [1892]; middle Silurian rocks of Canada. Canadian Naturalist 5(3): 8:2: 1–317 [1893]; 8:2: 319–394, pls. 21–84 [1895]. 49–69. Harper, C.W. 1973. Brachiopods of the Arisaig Group (Silurian- Boucot, A.J. 1975. Evolution and extinction rate controls. Develop- Lower Devonian) of Nova Scotia. Geological Survey of Canada ments in Paleontology and stratigraphy 1, 423 p. Elsevier Bulletin 215: 163 pp., 3 figs, 28 pls. Ottawa. Publishing Co. Harper, C.W. Jr. and Boucot, A.J. 1978a. The Stropheodontacea, part Calef, C.E., and N.J. Hancock. 1974. Wenlock and Ludlow marine I. Palaeontographica (A) 161: 55–118, pl. 1–18. communities in Wales and the Welsh Borderlands. Palaeontol- Harper, C.W. Jr. and Boucot, A.J. 1978b. The Stropheodontacea, part ogy 17: 779–810. II. Palaeontographica (A) 161: 119–175, pl. 19–35. Caster, K.E. 1939. A Devonian fauna from Colombia. Bulletin of Harper, C.W. Jr. and Boucot, A.J. 1978c. The Stropheodontacea, part American Paleontology 24: 1–218, pl. 1–14. III. Palaeontographica (A) 162: 1–80, pl. 36–50. Cherns, L. 1982. Palaeokarst, tidal erosion surfaces and stromatolites Havlı´cˇek, V. 1967. Brachiopoda of the suborder Strophomenidina in in the Silurian Eke formation of Gotland, Sweden. Sedimentol- Czechoslovakia. Rozpravy U´strˇenı´ho u´stavu geologicke´ho 33: ogy 29: 819–833. 235 p, 52 pls. Praha. Cherns, L. 1983. The Hemse-Eke Boundary. Facies relationships in Hede, J.E. 1921. Gottlands Silurstratigrafi. Sveriges Geologiska the Ludlow Series of Gotland, Sweden. Sveriges Geologiska Underso¨kning C 305: 1–100. Underso¨kning C 800: 44 p. Hede, J.E. 1925. Berggrunden (Silursystemet). In Munthe, H., Hede, Cocks, L.R.M. 1968. Some strophomenacean brachiopods from the J.E. and von Post, L., Kartbladet R.. Sveriges Geologiska British Lower Silurian. British Museum (Natural History), Underso¨kning Aa, Vol. 156, pp. 14–51. Bulletin (Geology) 15(6): 283–324. Hede, J.E. 1960. The Silurian of Gotland. In Regne´ll, G. and Hede, Cocks, L.R.M. 1978. A review of British Lower Palaeozoic brachio- J.E., The lower Palaeozoic of Scania and the Silurian of Gotland. pods, including a synoptic revision of Davidson’s monograph. 21st International Geological Congress; Guide to excursions London: Monographs of the Palaeontographical Society. 256 p. A22 and C17: 44–89. Sveriges Geologiska Underso¨kning. Cocks, L.R.M., and J.-Y. Rong. 2000. Strophomenida. In Treatise on Hoel, O.A. 2005. Silurian Leptaeninae (Brachiopoda) from Gotland, Invertebrate Paleontology. Part H: Brachiopoda (Revised), Vol Sweden. Pala¨ontologische Zeitschrift 79(2): 263–284. 2–3, ed. A. Williams, C.H.C. Brunton, and S.J. Carlson, Hoel, O.A. 2007. Cementing strophomenide brachiopods from the 216–348. Boulder, CO: University of Kansas. Silurian of Gotland (Sweden): Morphology and life habits. Cocks, L.R.M., and D. Worsley. 1993. Late Llandovery and early Geobios 40: 589–608. Wenlock stratigraphy and ecology in the Oslo Region, Norway. Hoel, O.A. 2008. Evidence for muscular control of the apical pedicle Bulletin of The Natural History Museum (Geology) 49(1): 31–46. in a Silurian Leptaenine brachiopod from, Gotland, Sweden, and Conrad, T.A. 1842. Observations on the Silurian and Devonian its life position. Fossils and Strata 54: 53–58. systems of the United States, with descriptions of new organic Holland, C.H., Lawson, J.D. and Walmsley, V.G. 1963. The Silurian remains. Journal of the Academy of Natural Sciences Philadel- rocks of the Ludlow district, Shropshire. Bulletin of British phia 8: 228–280. Museum of Natural History (Geology) 8: 93–171, pls. 1–7. Cooper, G.A. 1956. Chazyan and related brachiopods. Smithsonian Holtedahl, O. 1916. The Strophomenidae of the Kristiania Region. miscellaneous Collections 127 (1): 1–1024, (2): 1025–1245, pl. Det Norske Vitenskaps-Akademi i Oslo. I. Skrifter. Matematisk- 1–269. Naturvitenskapelig Klasse 1915 (No. 12): 1–117, pl. 1–16. Davidson, T. 1847. Observations on some of the Wenlock-limestone Kelly, F.B. 1967. Silurian Leptaenids (Brachiopoda). Palaeontology Brachiopoda, with descriptions of several new species. London 10(4): 590–602. Geological Journal 1: 52–65, pl. 12–13. King, W. 1846. Remarks on certain genera belonging to the class Davidson, T. 1848. Me´moire sur les Brachiopodes du Syste`me Palliobranchiata. Annals and Magazine of Natural History Silurien supe´rieur de l’Angleterre. Socie´te´ Ge´ologique de (series 1) 18: 26–42, 83–94. France, Bulletin (series 2) 5:309–338, 370–374, 2 pl. La Touche, J.D. 1884. A Handbook of the Geology of Shropshire. Davidson, T. 1866–1871. A monograph of the British fossil 91 pp., 22 pls. London and Shrewsbury. Brachiopoda. Vol. 3, Part 7, Silurian. Palaeontographical Lamont, A. and Gilbert, D.L.F. 1945. Upper Llandovery brachiopoda Society [Monograph]: No. 1, 1866, 1–88, Pls. 1–12; No. 2, from Coneygore Coppice and Old Storridge Common, near 1867, 89-168, Pls. 13–22; No. 3, 1869, 169–248, Pls. 23–37; No. Alfrick, Worcestershire. Annual Magazine of Natural History 4, 1871, 249–397, Pls. 38–50. (11) 12: 641–682, pl. 3–7. Davidson, T. 1883. A Monograph of the British Fossil Brachiopoda, Laufeld, S. 1974. Silurian Chitinozoa from Gotland. Fossils and Vol. 5. Silurian Supplement, part 2. Palaeontographical Society Strata 5: 1–130. Monograph. 135–242, pl. 8–17. London. Laufeld, S., and M.G.B. Bassett. 1981. Gotland: The anatomy of a Dawson, J.W. 1880. New facts respecting the geological relations and Silurian carbonate platform. Episodes 1981(2): 23–27. fossil remains of the Silurian iron-ores of Pictou, Nova Scotia. Lindstro¨m, G. 1861. Bidrag till ka¨nnedomen om Gotlands brachio- Canadian Naturalist and Geologist (new series) 9: 332–344. poder. O¨fversikt af Kungliga Vetenskapsakademiens Fo¨rhand- Dewing, K. 1999. Late Ordovician and Early Silurian strophomenid lingar Stockholm 17 [fo¨r 1860]: 337–382, pl. 12–13. brachiopods of Anticosti Island, Que´bec, Canada. Palaeonto- M’Coy, F. 1846. A synopsis of the Silurian fossils of Ireland collected graphica Canadiana 17: 143 pp. from the several districts by Richard Griffith, F.G.S. 72 p, 5 pls., de Verneuil, E. 1848. Notes sur quelques brachiopodes de l’ile de Dublin. Gotland. Bulletin de Societe´ Ge´ologique de France (2) 5: Manten, A.A. 1971. Silurian reefs of Gotland. Developments in 339–347, pl. 4. Sedimentology 13: 539 p. Amsterdam (Elsevier).

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McClearn, F.H. 1924. Paleontology of the Silurian Rocks of Arisaig, Salter, J.W. In: Murchison, R.I. 1854. Siluria. The history of the Nova Scotia. Geological Survey of Canada Memoir 137: 1–179, oldest known rocks containing organic remains, with a brief 30 pls. description of the distribution of gold over the earth. I–xvi, Munthe, H. 1902. Stratigrafiska studier o¨fver Gotlands Silurlager 192: 1–523, pls. 1–37. London. 55 p. Sveriges Geologiska Underso¨kning C 192: 55p. Also in: Samtleben, C., A. Munnecke, T. Bickert, and J. Pa¨tzold. 1996. The Geologiska Fo¨reningen i Stockholms Fo¨rhandlingar 24(4): Silurian of Gotland (Sweden): Facies interpretation based on 221–273. stable isotopes in Brachiopod shell. Geologische Rundschau 85: Munthe, H., Hede, J.E. and von Post, L. 1925. Gottlands Geologi. En 278–292. o¨versikt. Sveriges Geologiska Underso¨kning C 331: 130 p. Shaler, N.S. 1865. List of the Brachiopoda from the Island of Murchison, R.I. 1839. The Silurian System. Founded on geological Anticosti sent by the Museum of Comparative Zoology to researches in the counties of Salop, Hereford, Radnor, Mont- different institutions in exchange for other specimens, with gomery, Caermarthen, Pembroke, Monmouth, Gloucester, annotations. Bulletin of the Museum of Comparative Zoology, Worcester, and Stafford; with descriptions of the coalfields and Harvard 1: 61–70. overlying formations. i–xxxii, 768 p., 37 pls., London. Sowerby, J. de C. 1824, 1839 and 1842. In: Sowerby, J. and Sowerby, Musteikis, P., and L.R.M. Cocks. 2004. Strophomenide and orthote- J. de C. 1812–1846. The Mineral Conchology of Great Britain; tide Silurian brachiopods from the Baltic region, with particular or coloured figures and descriptions of those remains of reference to Lithuanian boreholes. Acta Palaeontologica Polo- testaceous animals or shells, which have been preserved at nica 49(3): 455–482. various times and depths in the earth. 7 volumes, pl. 1–383 Nikiforova, O.I., Modzalevskaya, T.L. and Bassett, M.G. 1985. (1812–1822) by J. Sowerby; pl. 384–648 (1823–1846) by J. de Review of the upper Silurian and lower Devonian articulate C. Sowerby, London. brachiopods of Podolia. Special Papers in Palaeontology 34: Thomsen, E. and Baarli, B.G. 1982. Brachiopods of Lower Llando- 66 p. very Sælabonn and Solvik formations of the Ringerike, Asker Paeckelmann, W. and Sieverts, H. 1932. Ober-silurische und and Oslo districts. In Field Meeting, Oslo Region 1982, ed. devonische Faunen der Prinzeninseln, Bithyniens und Thraziens. Worsley, D. Palaeontological Contributions of the University of Abhandlungen der Preussischen Geolologischen Landesanstalt, Oslo, Vol 278, pp. 63–78. Berlin (new series) 142: 1–79, 4 pls. Torsvik, T., M. Smethurst, J.G. Meert, R. Van der Voo, W.S. Pander, C.H. 1830. Beitra¨ge zur Geognosie des Russichen Reiches. McKerrow, M.D. Brasier, B.A. Sturt, and H.J. Walderhaug. xx ? 165 p., 31 pls., St. (Gedruckt bei K. Kray): Petersburg. 1996. Continental break-up and collision in the Neoproterozoic Phillips, J. and Salter, J.W. 1848. Palaeontological appendix to and Palaeozoic; a tale of Baltica and Laurentia. Earth-Science Professor John Phillips’ Memoir on the Malvern Hills compared Reviews 40(3–4): 229–258. with the Palaeozoic districts of Abberley etc. Memoirs of the Williams, A. 1951. Llandovery brachiopods from Wales with special Geological Survey of Great Britain, London 2(1): 331–386, reference to the Llandovery district. Quarterly Journal of the pl. 4–30. Geological Society of London 107: 85–136, pl. 3–8. Reed, F.R.C. 1917. The Ordovician and Silurian Brachiopoda of the Williams, A. 1953. North American and European Strophodontids, Girvan district. Transactions of the Royal Society of Edinburg their morphology and systematics. Memoirs of the Geological 51: 795–998, pl. 1–24. Society of America 56: 1–67, 13 pls. Richardson, J.R. 1997. Ecology of articulated brachiopods. In Williams, A. 1965. Suborder Strophomenidina. In Treatise on Treatise on Invertebrate Paleontology. Part H, Brachiopoda Invertebrate Paleontology. Part H, Brachiopoda, ed. Moore, (Revised), Vol. 1, ed. Kaesler, R.L., 441–462, Boulder & R.C., 362–412. New York and Lawrence (The Geological Lawrence (The Geological Society of America & The University Society of America and The University of Kansas Press). of Kansas). Williams, A., C.H.C. Brunton, and S.J. Carlson. 1997. Treatise on Rong J.-Y. and Cocks, L.R.M. 1994. True Strophomena and a Invertebrate Paleontology. Part H, Brachiopoda (Revised). revision of the classification and evolution of strophomenoid and Volume 1: Introduction. 539 p. Boulder, CO: The Geological ‘‘strophodontoid’’ brachiopods. Palaeontology 37: 651–694, pl. Society of America Inc. and The University of Kansas. 1–7. Winchell, N.H., and C. Schuchert. 1892. Preliminary descriptions of Rybnikova, M.V. 1966. Some Strophomenid brachiopods from the new Brachiopoda from the Trenton and Hudson River Groups of upper Silurian rocks of Latvia [in Russian]. In Paleontologiaˆ i Minnesota. American Geologist, Minneapolis 9: 284–294. stratigrafiaˆ Pribalitiki i Belorussii, Vol. 1, ed. Grigelius, A.A., Worsley, D., N. Aarhus, M.G. Bassett, M.P.A. Howe, A. Mørk, and 75–95, Vilnius (Mintis). S. Olausen. 1983. The Silurian succession of the Oslo Region. Rybnikova, M.V. 1967. Phylum Brachiopoda [in Russian]. In Norges Geologiske Undersøkelse Bulletin 72: 1–57. Stratigrafiaˆ, fauna i usloviaˆ obrozovaniaˆ silurijskih porod Ziegler, A.M., L.R.M. Cocks, and R.K. Bambach. 1968. The Pribaltiki, eds. Gailite, L.K., Rybnikova, M.V. & Ulst, R.Z., composition and structure of lower Silurian Marine communi- 169–221, Riga (Zinatne). ties. Lethaia 1: 1–27.

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